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Stir bar sorptive extraction: Recent applications, limitations and future trends
Abstract
Stir bar sorptive extraction (SBSE) has generated growing interest due to its high effectiveness for the extraction of non-polar and medium-polarity compounds from liquid samples or liquid extracts. In particular, in recent years, a large amount of new analytical applications of SBSE has been proposed for the extraction of natural compounds, pollutants and other organic compounds in foods, biological samples, environmental matrices and pharmaceutical products. The present review summarizes and discusses the theory behind SBSE and the most recent developments concerning its effectiveness. In addition, the main results of recent analytical approaches and their applications, published in the last three years, are described. The advantages, limitations and disadvantages of SBSE are described and an overview of future trends and novel extraction sorbents and supports is given.
... Additionally, reliable and precise analytical results are critical for judicial decisions (He & Concheiro-Guisan, 2019). Sample preparation aims to reduce or eliminate the interferences (proteins, salts, organic compounds, etc.), extract, and preconcentrate the analytes of interest to improve the sensitivity, specificity, and selectivity of the analytical methods (Camino-Sánchez et al., 2014;Greco et al., 2023;He & Concheiro-Guisan, 2019). ...
... PDMS is a nonpolar polymeric phase that promotes hydrophobic interactions with the analytes of interest. The possible retention mechanisms include van-der-Waals forces and hydrogen bonds between the oxygen atoms of PDMS and the organic analytes, depending on their molecular structure (Camino-Sánchez et al., 2014;Marín-San Román et al., 2022;Nogueira, 2012). The presence of glass in the Twister is critical to avoiding catalytic decomposition of the coating material by direct contact with the magnetic bar, especially during thermal desorption (Nazyropoulou & Samanidou, 2015). ...
... The K o/w coefficient is only used for the PDMS extraction phase. If the sorbent materials are different, proper distribution constants should be chosen (Camino-Sánchez et al., 2014). ...
... The extraction process can occur in two modes: immersion or headspace (Figure 4). In the immersion mode, the SBSE device is immersed in the aqueous sample and, under controlled physical and chemical conditions with stirring, the stir bar adsorbs the target organic compounds to be extracted [131,132]. Bicchi et al. expanded this technique to analyze samples in the vapor phase, known as headspace sorptive extraction (HSSE) [133]. In the headspace mode, similar to SPME, the coated stir bar is suspended in the headspace vial, allowing the polymer to come into contact with the vapor phase of a solid or liquid sample matrix [132]. ...
... Although SBSE offers several advantages, it is important to acknowledge its limitations, which include (1) a restricted range of analyte polarities due to the available stationary phases, (2) susceptibility to strong matrix effects, and (3) the requirement for precise control of extraction conditions [92]. A recent study aiming to observe the impact of using different sample preparation techniques (dynamic headspace (DHS), vortex-assisted liquid-liquid microextraction (VALLME), multiple stir bar sorptive extraction (mSBSE), solid-phase extraction (SPE), and solid phase micro-extraction (SPME)) to figure out the most suitable sample preparation protocol for profiling In the immersion mode, the SBSE device is immersed in the aqueous sample and, under controlled physical and chemical conditions with stirring, the stir bar adsorbs the target organic compounds to be extracted [131,132]. Bicchi et al. expanded this technique to analyze samples in the vapor phase, known as headspace sorptive extraction (HSSE) [133]. In the headspace mode, similar to SPME, the coated stir bar is suspended in the headspace vial, allowing the polymer to come into contact with the vapor phase of a solid or liquid sample matrix [132]. ...
... SBSE has addressed certain limitations observed in SPME, as demonstrated by various researchers. With its pre-concentration capability, broad application range, and simplicity, SBSE is emerging as one of the most extensively investigated sample extraction techniques for organic compound analysis [131]. In a study comparing HS-SPME and SBSE, Castro and Ross found that SBSE exhibited higher recovery rates, indicating its effectiveness [106]. ...
Owing to the unique chemical properties exhibited by beer flavor compounds, different extraction methods have been utilized to extract these compounds from the sample matrix. Carbonyl compounds, which significantly contribute to flavor instability in beer, pose challenges in detection due to their low concentrations and reactivity. Consequently, the analysis of beer flavor compounds has focused on improving sensitivity and specificity through techniques that minimize sample preparation requirements and reduce interactions between factors involved in the analysis. Notably, extraction techniques such as headspace solid-phase microextraction (HS-SPME), stir bar sorptive extraction (SBSE), and gas diffusion microextraction (GDME) have been successfully applied to the analysis of carbonyl compounds in alcoholic beverages, including beer. Derivatization agents like 2,4-dinitrophenylhydrazine (DNPH) and O-(2,3,4,5,6-pentafluorobenzyl)hydroxylamine (PFBHA) enhance the volatility and stability of analytes, facilitating their separation and detection in gas chromatography and high-performance liquid chromatography. Chromatographic separation methods, particularly gas chromatography and liquid chromatography, are extensively employed to identify and quantify aroma/flavor compounds in various foodstuffs, including beer. This review provides a comprehensive overview of extraction techniques and chromatographic methods used in the analysis of beer compounds.
... The first task in the BAµE optimization process is the selection of the most suitable sorbent phase for the target analytes involved. Afterwards, several experimental parameters were studied using one-variable-at-a-time (OVAT) strategy, both for microextraction and back-extraction stages, including the desorption solvent and time, stirring rate, matrix pH, organic modifier, ionic strength, equilibrium time, and sample dilution effect, according to previous reports [8,23,[28][29][30][31][32][33][34][35][36]. Although OVAT does not allow the identification of possible interactions between variables and requires many assays, this strategy is easy to implement in this type of optimizations since the number of variables is low and no relevant interactions are expected in compliance with our expertise [8,37]. ...
... It is usually employed to minimize the possible adsorption of the analytes to the glass walls of the sampling flask ("wall-effect"), which generally occurs for compounds with log KO/W higher than 4. However, it can also lead to a solubility increment of the analytes in the aqueous media, hindering the microextraction process [8,28]. As expected, and once the six TCAs present log KO/W lower than 5, the best results were attained without MeOH addition. ...
... It is usually employed to minimize the possible adsorption of the analytes to the glass walls of the sampling flask ("wall-effect"), which generally occurs for compounds with log K O/W higher than 4. However, it can also lead to a solubility increment of the analytes in the aqueous media, hindering the microextraction process [8,28]. As expected, and once the six TCAs present log K O/W lower than 5, the best results were attained without MeOH addition. ...
This work entailed the development, optimization, validation, and application of a novel analytical approach, using the bar adsorptive microextraction technique (BAμE), for the determination of the six most common tricyclic antidepressants (TCAs; amitriptyline, mianserin, trimipramine, imipramine, mirtazapine and dosulepin) in urine matrices. To achieve this goal, we employed, for the first time, new generation microextraction devices coated with convenient sorbent phases, polymers and novel activated carbons prepared from biomaterial waste, in combination with large-volume-injection gas chromatography-mass spectrometry operating in selected-ion monitoring mode (LVI-GC-MS(SIM)). Preliminary assays on sorbent coatings, showed that the polymeric phases present a much more effective performance, as the tested biosorbents exhibited low efficiency for application in microextraction techniques. By using BAμE coated with C18 polymer, under optimized experimental conditions, the detection limits achieved for the six TCAs ranged from 0.2 to 1.6 μg L⁻¹ and, weighted linear regressions resulted in remarkable linearity (r² > 0.9960) between 10.0 and 1000.0 μg L⁻¹. The developed analytical methodology (BAμE(C18)/LVI-GC-MS(SIM)) provided suitable matrix effects (90.2–112.9%, RSD ≤ 13.9%), high recovery yields (92.3–111.5%, RSD ≤ 12.3%) and a remarkable overall process efficiency (ranging from 84.9% to 124.3%, RSD ≤ 13.9%). The developed and validated methodology was successfully applied for screening the six TCAs in real urine matrices. The proposed analytical methodology proved to be an eco-user-friendly approach to monitor trace levels of TCAs in complex urine matrices and an outstanding analytical alternative in comparison with other microextraction-based techniques.
... Therefore, temperature and extraction time should balance for best results. 22 Whereas the advances in experimentation have significantly widened the applications of SBSE, understanding the mechanisms at the molecular level has not been a priority. This is where computational techniques, particularly molecular dynamics (MD) simulations, can offer a reliable way of bridging experimental gaps and looking deeper into the molecular processes of stir bar sorptive extraction. ...
... All simulations involve only one type of organic molecule in order to simplify the analysis, and at experimental conditions. 20,22 The maximum number of organic molecules placed in the aqueous phase was calculated according to the limit of its solubility in water. ...
Separation processes relying on interfacial interactions, such as the stir bar sorptive extraction represent one of the most critical methods of analyte trace organic detection and extraction in environmental, food, and biomedical samples. While the use of polydimethylsiloxane (PDMS) as a sorptive coating in SBSE has exhibited high sensitivity and efficiency; the molecular mechanisms involved are less explored. We report molecular simulation studies using molecular dynamics (MD) to investigate the absorption of organic compounds including phenol, chlorophenol, guaiacol, benzyl alcohol, and phenethyl alcohol at the aqueous-PDMS interface, and focus on temperature-dependent behavior. By employing an appropriate force field for PDMS, organic compounds, and water, these simulations directly predict PDMS-water partition coefficients, log P [PDMS/water], diffusion coefficients, and solubilities in the PDMS phase without relying on octanol–water partitioning as a surrogate. An important result of the MD simulations in this work is our ability to predict the temperature dependence of the log p(PDMS/water). Results reveal a nonmonotonic temperature-dependent sorption trend for log P [PDMS/water] values. However, we find that with increasing temperature, the absolute number of organic molecules in the PDMS phase increases, driven by enhanced molecular diffusion and PDMS’s significant sorption capacity. The findings demonstrate that performing SBSE at elevated temperatures can enhance analyte uptake, improving the analytical sensitivity of trace level extractions, where achieving sufficient analyte concentration in the sorptive phase is critical for reliable detection and quantification in a wide variety of applications in environmental monitoring, food safety, and biomedical analysis. These simulations predict that temperature is a good parameter for the optimization of operating conditions of SBSE. Our results also highlight the ability of MD simulations to reliably capture complex molecular level interactions governing SBSE performance, aligning well with experimental trends and observed behaviors.
... Many reviews summarized the developments in SBSE, with the first 10-year period thoroughly described by Prieto et al. [142] and the developments of recent decades described by David et al. [143]. The sensitivity obtained by SBSE, which made it the preferred technique for many trace analyses, is related to the volume of PDMS compared to other techniques in which PDMS is used as an absorbent (i.e., SPME), though the desorption of analyte from such a high-volume (and thick layer) sorbent also poses problems for carry over and incomplete desorption of compounds absorbed into PDMS (memory effect) [144]. The benefits of SBSE compared to other techniques are presented in Figure 3, which shows the comparison of theoretical recoveries of analytes as a function of the octanol/water partition coefficient (log K ow ). ...
... It is evident that, especially for compounds with lower log K ow , SBSE is superior to SPME or Arrow-SPME (which operates similarly to SPME but has more sorbent) in terms of extraction yield. sorbent also poses problems for carry over and incomplete desorption of compounds absorbed into PDMS (memory effect) [144]. The benefits of SBSE compared to other techniques are presented in Figure 3, which shows the comparison of theoretical recoveries of analytes as a function of the octanol/water partition coefficient (log Kow). ...
This review presents an outline of the application of the most popular sorbent-based methods in food analysis. Solid-phase extraction (SPE) is discussed based on the analyses of lipids, mycotoxins, pesticide residues, processing contaminants and flavor compounds, whereas solid-phase microextraction (SPME) is discussed having volatile and flavor compounds but also processing contaminants in mind. Apart from these two most popular methods, other techniques, such as stir bar sorptive extraction (SBSE), molecularly imprinted polymers (MIPs), high-capacity sorbent extraction (HCSE), and needle-trap devices (NTD), are outlined. Additionally, novel forms of sorbent-based extraction methods such as thin-film solid-phase microextraction (TF-SPME) are presented. The utility and challenges related to these techniques are discussed in this review. Finally, the directions and need for future studies are addressed.
... In many cases, commercially available coatings such as, PDMS [81,82], polyacrylate (PA) and silicone coatings (EG) are used. As can be seen in articles [76,77] PDMS coating can efficiently extract less polar compounds due to its good hydrophobic strength, whereas PA and EG are repurposed for compounds with higher polarity [83]. These polymeric stirrers have an expiry date. ...
... The need for ensuring the safety of edible products, including grapes, has led scientists in quality control laboratories all over the world to look for new, cheap, and environmentally friendly analytical techniques. As a result, the SPME method has found its application for the extraction of different classes of pesticide residues in various food matrices, including grapes [83,84,94,97]. SPME is a very versatile sample preparation method, due to the possibility of fiber modifications. ...
Pesticides are major contaminants in grapes and their by-products. Different methods for sample preparation and separation are used for determining different pesticides in grapes. However, until now, the environmental friendliness of these methods has not been assessed fully. At present time, several tools such as Eco-Scale, NEMI, GAPI, AGREE are available to evaluate the environmental sustainability of methods such as sample preparation, extraction, and separation. Each tool has its benefits and drawbacks. Moreover, the results obtained with the help of each tool may lead to different conclusions. This paper is aimed to review different sample preparation methods for the determination of pesticides in grapes found in the scientific literature. The Green Analytical Procedure Index (GAPI) tool was chosen to evaluate the environmental friendliness of each methodology in this study. This research also shows the importance of using aforementioned tools in the development of future analytical methods before using practical tests. In addition to greenness, tool helps to assess assessing minimize the use of chemical hazards and avoid risks to human health and emissions to the environment. Method greenness assessment is suggested to be included in method validation protocols.
... The sample preparation step helps to isolate the analyte(s) of interest, and to clean-up and preconcentrate the analyte(s) for better detection. Moreover, sample preparation is important for enhancing the selectivity and sensitivity of the analytical method [118]. Sample extraction is a technique in which sorbent is used to extract analyte(s) from the sample. ...
... The bar will be introduced into the sample solution and stirred for extraction process. The bar will then be removed from the sample, dried, and desorbed using solvent [118]. Thus, in the technique, montmorillonite was coated onto the glass magnetic bar by using an epoxy resin, which exhibited robust support with excellent mechanical stability. ...
The wide spread of phenols and their toxicity in the environment pose a severe threat to the existence and sustainability of living organisms. Rapid detection of these pollutants in wastewaters has attracted the attention of researchers from various fields of environmental science and engineering. Discoveries regarding materials and method developments are deemed necessary for the effective detection and remediation of wastewater. Although various advanced materials such as organic and inorganic materials have been developed, secondary pollution due to material leaching has become a major concern. Therefore, a natural-based material is preferable. Clay is one of the potential natural-based sorbents for the detection and remediation of phenols. It has a high porosity and polarity, good mechanical strength, moisture resistance, chemical and thermal stability, and cation exchange capacity, which will benefit the detection and adsorptive removal of phenols. Several attempts have been made to improve the capabilities of natural clay as sorbent. This manuscript will discuss the potential of clays as sorbents for the remediation of phenols. The activation, modification, and application of clays have been discussed. The achievements, challenges, and concluding remarks were provided.
... Other benefits of this technique rely on the possibility of automation and compatibility with different systems of analyte separation and detection [60]. As a result, all analytical domains, including environmental, clinical, and food analysis, as well as a wide range of matrices, including soils, environmental water and wastewater, solid and liquid foods, gaseous samples, and biological fluids, have efficiently resorted to this extraction technique [59,60,62,63]. ...
... However, this restriction can be overcome, and the use of SBSE expanded, to include polar and thermally labile molecules by combining SBSE with a derivatization procedure [60]. The main disadvantage of this technique is the limited range of commercial coatings, consequently limiting the spectrum of analyte polarities (highly polar or hydrophilic solutes) [61][62][63]. Upton that, this technique is well-known for analytical methods with a high enrichment factor for a wide range of non-polar species (the most common) [62]. The most common coatings commercially available are polydimethylsiloxane (PDMS), polyethylene (PEG), and polyacrylate (PA) [62]. ...
Natural products are increasingly becoming part of our daily lives through their use in industry, food, as therapeutic agents, etc. To evaluate their possible applications, it is essential to characterize them chemically to explore their potential. Different techniques may be used to characterize natural products, including microextraction techniques. These techniques have been gaining popularity due to the advantages associated with their low use of organic solvents and the small amount of sample used relative to more classical sample preparation techniques. Their application in the extraction of compounds from natural products is still scarce. This manuscript intends to review the most used solid-based miniaturized sample preparation techniques applied to determining compounds in natural products. The main applications of these methodologies will be discussed, with a particular focus on natural product analysis, as well as their advantages and disadvantages over traditionally used sample preparation techniques.
... SBSE has been successfully applied to pharmaceutical analysis in different kinds of matrices, including environmental water, biological fluids, soils, and gaseous samples (Vo Duy et al., 2012;Hu et al., 2013). Several trials have been going on to improve the SBSE efficiency and its recent developments (Amlashi and Hadjmohammadi, 2016); nevertheless, the number of applications within this field is lower than that in food and environment analyses (Camino-Sánchez et al., 2014). This could be related to the complexity of the biological matrix where SBSE is not a highly selective or specific extraction technique. ...
... This could be related to the complexity of the biological matrix where SBSE is not a highly selective or specific extraction technique. Moreover, many pharmaceutical analytes are polar compounds, and they have reduced extraction efficiency when PDMS is in the stationary phase (Camino-Sánchez et al., 2014;Taraji et al., 2015). Some approaches were carried out recently to increase the recovery of polar analytes, for instance, in situ derivatization and SBSE with solvent-swollen PDMS (Ochiai et al., 2018). ...
Extensive efforts have been made in the last decades to simplify the holistic sample preparation process. The idea of maximizing the extraction efficiency along with the reduction of extraction time, minimization/elimination of hazardous solvents, and miniaturization of the extraction device, eliminating sample pre- and posttreatment steps and reducing the sample volume requirement is always the goal for an analyst as it ensures the method’s congruency with the green analytical chemistry (GAC) principles and steps toward sustainability. In this context, the microextraction techniques such as solid-phase microextraction (SPME), stir bar sorptive extraction (SBSE), microextraction by packed sorbent (MEPS), fabric phase sorptive extraction (FPSE), in-tube extraction dynamic headspace (ITEX-DHS), and PAL SPME Arrow are being very active areas of research. To help transition into wider applications, the new solventless microextraction techniques have to be commercialized, automated, and validated, and their operating principles to be anchored to theory. In this work, the benefits and drawbacks of the advanced microextraction techniques will be discussed and compared, together with their applicability to the analysis of pharmaceuticals in different matrices.
... borneol, α-humulene, germacrene D, α-selinene, sabinene, β-selinene, caryophyllene oxide, α-pinene, camphene, α-cubebene, (E)-β-ocimene, limonene, 1,8-cineole, α-copaene, (Z)-3-hexenol and (3E)-hexenyl acetate were also found in essential oils of holy basil (Wongpraneekul et al., 2022). However, hydrodistillation and headspace extraction had limitations in term of compound degradation and artifact formation due to the elevated temperature (Camino-Sánchez et al., 2014;Etievant, 1996). Solventassisted flavor evaporation (SAFE) was a mild volatile-compound isolation technique which prevented compound degradation and artifact formation, thus preserving aroma profile of the extract nearly identical to that of fresh sample (Engel et al., 1999). ...
White holy basil is widely used in Thailand food industry. In this work, the sensomic approach (SAFE, GC-O/FID and GC-MS/MS) with sensory evaluation to identify aroma-active components was applied. Eight odor attributes of fresh holy basil were identified (i.e. clove-like, herb-terpeny, green, waxy, flowery, cucumber, sweet and woody). Thirteen aroma-active compounds (mostly terpenes such as α-pinene, camphene, sabinene, and limonene) were identified in white holy basil leaves. Eugenol (clove-like odor), 3-hexenal (grassy, green odor), α-pinene (terpeny, herb, resin-like odour), trans-β-farnesene (floral, herb-terpeny odor), and caryophyllene oxide (citrus-like, woody, herb-terpeny odor) were identified as aroma-active compounds. Recombined flavor mixture enhanced the aroma liking of stirred fried chicken with white holy when combined with fresh white holy basil leaves as Thai consumer liked the aroma of the sample over the aromas of the dishes made with fresh holy basil leaves alone and made with the recombined flavor alone.
... Additionally, SBSE can be applied in the study of bladder cancer, where the analysis of urine VOCs using SBSE may offer a noninvasive way to identify specific patterns associated with the disease. Overall, SBSE holds the potential in metabolomic study and provides a promising avenue for a robust and noninvasive cancer detection and biomarker discovery platform [111][112][113]. ...
Cancer is one of the leading causes of death globally, and is ranked second in the United States. Early detection is crucial for more effective treatment and a higher chance of survival rates, reducing burdens on individuals and societies. Genitourinary cancers, in particular, face significant challenges in early detection. Finding new and cost-effective diagnostic methods is of clinical need. Metabolomic-based approaches, notably volatile organic compound (VOC) analysis, have shown promise in detecting cancer. VOCs are small organic metabolites involved in biological processes and disease development. They can be detected in urine, breath, and blood samples, making them potential candidates for sensitive and non-invasive alternatives for early cancer detection. However, developing robust VOC detection methods remains a hurdle. This review outlines the current landscape of major genitourinary cancers (kidney, prostate, bladder, and testicular), including epidemiology, risk factors, and current diagnostic tools. Furthermore, it explores the applications of using VOCs as cancer biomarkers, various analytical techniques, and comparisons of extraction and detection methods across different biospecimens. The potential use of VOCs in detection, monitoring disease progression, and treatment responses in the field of genitourinary oncology is examined.
... 54 The stir bar coating can be immersed in the sample solution or fixed in the headspace of the sample to extract the target analyte and used for desorption and determination of the extracted analyte. 55 All the above sample pretreatment techniques have been widely applied in MIPS-based food analysis. Table 2 lists the advantages and disadvantages of the above techniques. ...
... As shown in the results, increasing the extraction temperature in this study positively affected extraction efficiency. Based on the results obtained in this design, the effect of changing the sample volume on the extraction efficiency was negative, because by reducing the sample volume, the extraction kinetics were improved and the extraction reached the equilibrium faster 45 . It is also obvious from the Pareto chart that although the pH value did not significantly affect the extraction efficiency, its interactions with NaCl content and sample volume were significant. ...
Quantifying small amounts of the 17-hydroxyprogesterone in various matrix is crucial for different purposes. In this study, a commercial polydimethylsiloxane stir bar was used to extract hormone from water and urine samples. Analysis was performed by high-performance liquid chromatography using a UV detector. The response surface methodology was used to optimize the desorption and extraction steps, with predicted optimal point relative errors of 1.25% and 6.40%, respectively. The optimized method was validated with a linear range of 1.21–1000.00 for aqueous and 2.43–2000.00 ng mL–1 for urine samples. The coefficient of determination was 0.9998 and 0.9967, and the detection limit of the proposed method was obtained to be 0.40 and 0.80 ng mL–1 for aqueous and urine samples, respectively. The recovery percentage and relative standard deviation within a day and between three days after the addition of three different concentration levels of the standard to the control sample were 87–103% and 0.4–3.6% for aqueous and 87.5–101% and 0.1–5.2% for urine samples, respectively. The results show that the proposed method can be appropriate and cost-effective for extracting and analyzing this hormone. In addition, using three different tools, the greenness of the proposed method was proven.
... In all these SBSE-based techniques the extraction process is kinetically controlled being influenced by the sample volume, sorbent dimensions, and stirring speed, and therefore they usually need relatively high volumes of sample or at least a minimal volume to cover the extraction device [39]. Thus, their miniaturization is challenging and they have been widely applied in environmental and food analysis, where sample volume may not be an issue [40,41]. ...
Miniaturization of the analytical process has been a widespread trend, and the sample preparation stage is not exempted from this downscaling. Since the introduction of microextraction techniques as miniaturization of classical extraction techniques, they have become one of the strengths in this field. However, some of the original approaches to these techniques did not fully cover all the current principles of Green Analytical Chemistry. For this reason, during the last years, much emphasis has been placed on reducing/eliminating toxic reagents, reducing the amount of the extraction phase, and searching for new greener, and more selective extractant materials. On the other hand, even though high accomplishments have been achieved, the same attention has not always been paid to reducing the amount of sample, which is essential when treating low-availability samples such as biological samples, or in developing portable devices. In this review, we intend to give the readership an overview of the advances toward further miniaturization of microextraction techniques. Finally, a brief reflection is made on the terminology used, or that should, in our opinion, be used to term these new generation of miniaturized microextraction approaches. To this regard, the term, 'ultramicroextraction' is proposed to refer to those approaches beyond microextraction.
... An aqueous sample is extracted by stirring for a predetermined time with a PDMS-coated stir bar. The stir bar is subsequently removed from the aqueous sample and the absorbed compounds are then thermally desorbed and analyzed by GCMS [40]. The advantage of the SBSE is its simplicity, robustness, cost-effectiveness, and environmental friendliness [39]. ...
Due to agricultural runoff, pesticides end up in aquatic ecosystems and some accumulate in marine bivalves. As filter feeders, bivalves can accumulate high concentrations of chemicals in their tissue representing a potential risk to the health of human and aquatic ecosystems. So far, most of the studies dealing with pesticide contamination in marine bivalves, for example, in the French Atlantic and English Channel coasts, have focused on the old generation of pesticides. Only a few investigated the newly emerging pesticides partly due to methodological challenges. A better understanding of the most sensitive and reliable methods is thus essential for accurately determining a wide variety of environmentally relevant pesticides in marine bivalves. The review highlighted the use of more environmentally friendly and efficient materials such as sorbents and the “quick easy cheap effective rugged safe” extraction procedure to extract pesticides from bivalve matrices, as they appeared to be the most efficient while being the safest. Moreover, this method combined with the high-resolution mass spectrometry (MS) technique offers promising perspectives by highlighting a wide range of pesticides including those that are not usually sought. Finally, recent developments in the field of ultra-high-performance liquid chromatography coupled to MS, such as two-dimensional chromatography and ion mobility spectrometry, will improve the analysis of pesticides in complex matrices.
... Stir bar coated with Polydimethyl siloxane (PDMS), a highly non-polar sorbent added into the sample solution and vortexed for a few minutes to adsorb the sample from the matrix followed by desorption into the solvent. The adsorbent coatings generally used are PDMS, ethylene glycol /silicone and polyacrylate where as PDMS sorbent was used for non-polar compounds, PA and EG /silicone sorbent were used for polar compounds [63] . Yao et al. analyzed quinolones in milk by using stirbar sorptive microextraction technique by using LC-Fluorescence detection analysis and have a detection capability of 0.2 ng/g of the sample weight [64] . ...
Antibiotics are life-saving medications for treating bacterial infections; however it has been discovered that resistance developed by bacteria against these incredible agents is the primary contributing factor to rising global mortality rates. The fundamental cause of the emergence of antibiotic resistance in bacteria is the presence of antibiotic residues in various environmental matrices. Although antibiotics are present in diluted form in environmental matrices like water, consistent exposure of bacteria to these minute levels is enough for the resistance to develop. So, identifying these tiny concentrations of numerous antibiotics in various and complicated matrices will be a crucial step in controlling their disposal in those matrices. Solid phase extraction, a popular and customizable extraction technology, was developed according to the aspirations of the researchers. It is a unique alternative technique that could be implemented either alone or in combination with other approaches at different stages because of the multitude of sorbent varieties and techniques. Initially, sorbents are utilized for extraction in their natural state. The basic sorbent has been modified over time with nanoparticles and multilayer sorbents, which have indeed helped to accomplish the desired extraction efficiencies. Among the current traditional extraction techniques such as liquid-liquid extraction, protein precipitation, and salting out techniques, solid-phase extractions (SPE) with nanosorbents are most productive because, they can be automated, selective, and can be integrated with other extraction techniques. This review aims to provide a broad overview of advancements and developments in sorbents with a specific emphasis on the applications of SPE techniques used for antibiotic detection and quantification in various matrices in the last two decades.
... SBSE is one of the main techniques for extracting volatile compounds from food used in the last decade [55], and is known for its sensitivity, high extraction capacity, high reproducibility and repeatability, when compared to other techniques such as solid phase microextraction (SPME), simultaneous distillation and extraction (SDE) and liquid-liquid extraction (LLE) [18,56]. The SBSE technique has already been used in several matrices for the extraction of volatile compounds, as an example we can mention freeze-dried omijas [57], apple pomace [58], peach juice [59], soursop powder [18], concentrated apple juice [60]. ...
Persimmon is a fruit much appreciated for its flavor and aroma, presenting high nutritional value and health-beneficial compounds. As it is a seasonal fruit, developing new products promotes its valorization as well as increasing its consumption, being drying a promising option. The objective of the present work was to produce persimmon powder by freeze drying and spray drying and to verify the effects of these drying methods on the retention of phenolic and volatile compounds of persimmon pulp. Phenolic compounds were analyzed in an liquid chromatograph coupled to a mass spectrometer (LC–MS), and volatile compounds were extracted by the stir bar sorptive extraction (SBSE) technique and analyzed in a gas chromatograph coupled to a mass spectrometer (GC–MS). A total of 15 phenolic compounds were identified among the analyzed samples, highlighting the sample obtained by spray drying (SD) that presented the largest number of phenolic compounds. SBSE-GC–MS analysis resulted in the identification of 81 volatile compounds, with alcohols, aldehydes, ketones and terpenes being the main chemical classes present in persimmon pulp and powders. The use of odor activity value (OAV) data made it possible to select 25 active odor compounds in persimmon pulp and powders, and that the decanal was the major contributor to the aroma of the samples. Among the rehydrated powders, 13 compounds presented higher OAV for the sample obtained by freeze drying with maltodextrin. Thus, we can conclude that the drying methods used were efficient in retaining the phenolic and volatile compounds in the persimmon pulp and that maltodextrin contributed positively to this retention, thus preserving the sensory quality of the pulp and its phenolic compounds.
... Despite this advantage, few papers on the use of PA and PEG have been published which is attributed to their mechanical instability. Since the SBSE introduction, it has gone through several improvements that focused on modifying the sorbent structure to provide more stable and efficient coatings [85]. Hence, the application of biodegradable materials as sorbent modifier has received considerable attention. ...
In recent years modification of sample preparation techniques has been in the spotlight for minimizing the volume of extraction solvent, increase the hydrophilicity of sorbent and decreasing the amount of sorptive phase to implement the principles of green chemistry. Significant progress has been made in sample preparation techniques to find greener solvents and sorbents. In this regard, the application of sample preparation techniques based on biodegradable materials has grabbed the attention of many researchers due to increasing concern about environmental degradation and resource depletion. Biodegradable materials with an environmentally friendly character emerged as sorbent or solvent in microextraction techniques. This review introduces the source and properties of biodegradable materials and discusses their analytical applications in liquid phase microextraction and sorbent-based microextraction techniques. The review also includes a comparison of new microextraction approaches with traditional methods to show their strengths.
... Traditional techniques such as SPME are still being improved thanks to advances in high-throughput instrumentation and data preprocessing (Kataoka et al. 2000). On the other hand, emerging technologies such as SBSE techniques are good alternatives as they require little sample preparation (David and Sandra 2007;Camino-Sánchez et al. 2014;Nogueira 2015). There is no singular method that allows for accurate, sensitive and complete reporting of chemical species but with these new analytical developments increased comprehensiveness is emerging. ...
... Moreover, the target desorption can also be performed with CE or even inductively coupled plasma. SBSE offers a higher preconcentration capacity when compared to SPME (Camino-Sánchez et al., 2014;Merkle et al., 2015). A schematic SBSE diagram is shown in Fig. 36.2. ...
This chapter discusses in detail the potential of several combined extraction and microextraction techniques for pretreating food waste. The discussion is focused on the combination of well-established methodologies such as ultrasound/microwave-assisted extraction and microwave-assisted acid digestion used for target extraction with preconcentration techniques such as those involving solid-based extraction/microextraction and solvent-based extraction/microextraction. The combined procedures allow target preconcentration, matrix (interferences) removal, and target transfer to a medium compatible with the selected instrumental analytical technique. Most of the combined microextraction procedures are consistent with the basic requirements of “green chemistry,” which is an important issue in modern analytical chemistry. Accomplishments, limitations, and future directions, mainly automation possibilities and new selective nano-structured materials, for food waste analyses are addressed.
... One of the major limitations of SBSE is the matrix efect (ME), which often occurs during the analysis of environmental samples, biological luids, or foods (Camino-Sánchez et al. 2014). In environmental water samples or organic solvent-water extracts obtained after previous extraction of solid matrices, high levels of dissolved organic matter may interfere with the extraction of the target compounds to the PDMS phase, and therefore, the extraction yield may be substantially changed compared to yield from the spiked pure water or organic solvent-water solution. ...
The study presents a fast and high throughput method for determination of short-chain chlorinated paraffins (SCCPs) together with other halogenated persistent organic pollutants (POPs) in sediment. The analytes (SCCPs, 11 polychlorinated biphenyls, 6 polybrominated diphenyl ethers, 11 organochlorine compounds) were determined in a single gas chromatography‒triple quadrupole tandem mass spectrometry (GC‒QqQ-MS/MS) run after miniaturized sample preparation combining ultrasonic solvent extraction (USE) and stir bar sorptive extraction (SBSE). The method was validated in terms of selectivity, matrix effect, matrix-matched recovery, linearity and range, detection and quantification limits (LOD and LOQ) and accuracy (including analysis of certified reference materials). The QqQ-MS/MS detector allowed the determination of all target analytes without interferences. The LODs and LOQs for SCCPs were 6.5 and 22 ng g‒1 dw (dry weight), while for other analytes were in the ranges 0.029‒0.073 ng g‒1 and 0.097‒0.24 ng g‒1, respectively. The recoveries for all the analytes were in the range 84‒101% with relative standard deviations in the range 5.5‒19%. In terms of environmental impact, the method was classified as “an excellent green analysis method”. Finally, the method was compared with other published methods and its applicability was confirmed by the analysis of sediment samples collected in 23 Slovak water reservoirs during a survey conducted in 2019.
... Samples with high organic matter or suspended solid components such as environmental samples, biological fluids or foods, are very difficult to extract with SBSE. Adsorption of the analytes onto the organic matter surface competes with the stir bar in the sorption [320]. Also, contamination of the sample by new pollution during the time between purification and reuse of the stirrer was also encountered [321]. ...
The objective of the present work was to evaluate the relevance of capillary electrophoresis (CE) method for the quantification of tyrosine kinase inhibitors (TKIs) in human plasma in the context of TDM. Four TKIs were selected for this study: imatinib mesylate, erlotinib hydrochloride, lapatinib ditosylate and sorafenib.A fast, simple and cost effective CZE-UV methodology for the quantification of imatinib in plasma was first developed using simply ACN precipitation as sample preparation before analysis. A complete study was performed to understand the electrophoretic behavior of imatinib in the presence of salt (from plasma) and ACN in the sample matrix. Then, a thorough study was performed to optimize an easy to use and performing sample pretreatment methodology based on salting-out assisted liquid-liquid extraction (SALLE) for the four TKIs from human plasma. SALLE, which is based on adding high concentration of salt to two miscible liquids, allows to extract in one step TKIs from plasma in an ACN phase with high recovery. The extracted TKIs can then be directly injected for further CZE-UV analysis. The use of ACN as extraction solvent allows to inject up to 80% of the capillary effective volumes. This allows in-line sample concentration through electrophoretic stacking mechanisms. In the perspective of routine use, the SALLE-CZE-UV methodology was fully automated. The analytical performances obtained for the four TKIs are fully suitable with TDM requirements. Finally, the SALLE-CZE-UV was successfully applied for the extraction and analysis of the four TKIs directly from human blood. All the present developments prove that CE is a relevant technique to address many TDM issues.
... Therefore, it is a necessary specially designed thermal desorption unit, which is only available in sophisticated instrumentation. Furthermore, some target compounds can be lost during the manual transfer of stir bar to the desorption device with a loss of sensitivity gained [156]. Another limitation is the number of commercially available sorptive phases, such as polydimethylsiloxane (PDMS), ethylene glycol (EG)-silicone, carboxen, carbowax-divinylbenzene (CW-DVB), and polyacrylate (PA). ...
In the environment, pharmaceutical residues are a field of particular interest due to the adverse effects to either human health or aquatic and soil environment. Because of the diversity of these compounds, at least 3000 substances were identified and categorized into 49 different therapeutic classes, and several actions are urgently required at multiple steps, the main ones: (i) occurrence studies of pharmaceutical active compounds (PhACs) in the water cycle; (ii) the analysis of the potential impact of their introduction into the aquatic environment; (iii) the removal/degradation of the pharmaceutical compounds; and, (iv) the development of more sensible and selective analytical methods to their monitorization. This review aims to present the current state-of-the-art sample preparation methods and chromatographic analysis applied to the study of PhACs in water matrices by pinpointing their advantages and drawbacks. Because it is almost impossible to be comprehensive in all PhACs, instruments, extraction techniques, and applications, this overview focuses on works that were published in the last ten years, mainly those applicable to water matrices.
... Stir bar sorptive extraction presents some drawbacks such as the limited range of analyte polarities for the available stationary phases, the presence of strong matrix effects, the requirement of a strict control of extraction parameters (Camino- Sánchez et al. 2014) and the complexity in the automation of the desorption step, especially to liquid chromatography (Chaves et al. 2007). At present, polydimethylsiloxane and ethylene glycol-silicone are the only commercially available phases in stir bar sorptive extraction. ...
Over the past few years, the presence of pesticides in foods has received growing attention as one of the main food safety problems. Many countries and health organizations have dictated increasingly strict regulations on the maximum pesticide residue limits on foodstuffs. Pesticides can also reach surface water through runoff from treated plants and soil, contaminate groundwater, soil, ground and grass, and be toxic to non-target organisms. Therefore, reliable methods for the analysis of pesticides need to be developed that can ensure accurate and precise results with sufficiently low detection limits for the determination of a wide range of these compounds. In most cases, these methods will need to include a sample pretreatment to extract, isolate, and concentrate the target compounds, as it is generally not possible to directly manipulate the sample.
Despite advancements in the sensitivity and performance of analytical instruments, sample preparation remains a bottleneck in the analytical process. Currently, solid-phase extraction is more widely used than traditional organic solvent extraction due to its ease of use and lower solvent requirements. Moreover, various microextraction techniques such as micro solid-phase extraction, dispersive micro solid-phase extraction, solid-phase microextraction, stir bar sorptive extraction, liquid-phase microextraction, and magnetic bead extraction have been developed to minimize sample size, reduce solvent usage, and enable automation. Among these, in-tube solid-phase microextraction (IT-SPME) using capillaries as extraction devices has gained attention as an advanced “green extraction technique” that combines miniaturization, on-line automation, and reduced solvent consumption. Capillary tubes in IT-SPME are categorized into configurations: inner-wall-coated, particle-packed, fiber-packed, and rod monolith, operating either in a draw/eject system or a flow-through system. Additionally, the developments of novel adsorbents such as monoliths, ionic liquids, restricted-access materials, molecularly imprinted polymers (MIPs), graphene, carbon nanotubes, inorganic nanoparticles, and organometallic frameworks have improved extraction efficiency and selectivity. MIPs, in particular, are stable, custom-made polymers with molecular recognition capabilities formed during synthesis, making them exceptional “smart adsorbents” for selective sample preparation. The MIP fabrication process involves three main stages: pre-arrangement for recognition capability, polymerization, and template removal. After forming the template-monomer complex, polymerization creates a polymer network where the template molecules are anchored, and the final step involves removing the template to produce an MIP with cavities complementary to the template molecules. This review is the first paper to focus on advanced MIP-based IT-SPME, which integrates the selectivity of MIPs into efficient IT-SPME, and summarizes its recent developments and applications.
From its introduction until now, more than 20 years ago, stir bar sorptive extraction (SBSE) has been consolidated as sample preparation technique. This chapter revisits the fundamentals of this solventless technique and discusses the different aspects affecting its performance, with special emphasis on working under non-equilibrium conditions. Special attention is focused on its limitations, mainly those derived for the extraction of non-polar compounds, and how researchers try to solve them by resorting to derivatization strategies, by developing new workflows and approaches, and/or by proposing new sorbents and synthetic procedures. Those SBSE-derived extraction techniques and the advantages they present are also described and deeply discussed. An exhaustive revision of those published papers just applying these techniques are not described considering they have been extensively compiled in recent published review articles, but those contributing with some of the above-mentioned developments are commented on.
Variations in salivary short-chain fatty acids and hydroxy acids (e.g., lactic acid, and 3-hydroxybutyric acid) levels have been suggested to reflect the dysbiosis of human gut microbiota, which represents an additional factor involved in the onset of heart failure (HF) disease. The physical-chemical properties of these metabolites combined with the complex composition of biological matrices mean that sample pre-treatment procedures are almost unavoidable. This work describes a reliable, simple, and organic solvent free protocol for determining short-chain fatty acids and hydroxy acids in stimulated saliva samples collected from heart failure, obese, and hypertensive patients. The procedure is based on in-situ pentafluorobenzyl bromide (PFB-Br) derivatization and HiSorb sorptive extraction coupled to thermal desorption and gas chromatography-tandem mass spectrometry. The HiSorb extraction device is completely compatible with aqueous matrices, thus saving on time and materials associated with organic solvent-extraction methods. A Central Composite Face-Centred experimental design was used for the optimization of the molar ratio between PFB-Br and target analytes, the derivatization temperature, and the reaction time which were 100, 60 °C, and 180 min, respectively. Detection limits in the range 0.1-100 µM were reached using a small amount of saliva (20 µL). The use of sodium acetate-1-13C as an internal standard improved the intra- and inter-day precision of the method which ranged from 10 to 23%. The optimized protocol was successfully applied for what we believe is the first time to evaluate the salivary levels of short chain fatty acids and hydroxy acids in saliva samples of four groups of patients: i) patients admitted to hospital with acute HF symptoms, ii) patients with chronic HF symptoms, iii) patients without HF symptoms but with obesity, and iv) patients without HF symptoms but with hypertension. The first group of patients showed significantly higher levels of salivary acetic acid and lactic acid at hospital admission as well as the lowest values of hexanoic acid and heptanoic acid. Moreover, the significant high levels of acetic acid, propionic acid, and butyric acid observed in HF respect to the other patients suggest the potential link between oral bacteria and gut dysbiosis.
Since environmental awareness has increased in analytical chemistry, the demand for green sample preparation methods continues to grow. Microextractions such as solid-phase microextraction (SPME) and liquid-phase microextraction (LPME) miniaturize the pre-concentration step and are a more sustainable alternative to conventional large-scale extractions. However, the integration of microextractions in standard and routine analysis methods is rare, although these applications are used most frequently and have a role model function. Therefore, it is important to highlight that microextractions are capable to replace large-scale extractions in standard and routine methods. This review discusses the greenness, benefits, and drawbacks of the most common LPME and SPME variants compatible with gas chromatography based on the following key evaluation principles: Automation, solvent consumption, hazards, reusability, energy consumption, time efficiency, and handling. Furthermore, the need to integrate microextractions into standard and routine analytical methods is presented by using method greenness evaluation metrics AGREE, AGREEprep, and GAPI applied to USEPA methods and their replacements.
Covering: 2000 to 2022This article reviews the latest developments of analytical methods of volatile natural products. Volatile organic compounds (VOCs) released from biological systems correspond to a series of compounds, originating from primary and secondary metabolites. These compounds are important for intra- and interspecies chemical communication and interaction of living organisms. These valuable natural products can find applications in many fields, including foods, human nutrition, pharmaceuticals, perfumes, cosmetics and so on. Therefore, the deciphering of their structures is of increasing importance in many fields of natural product chemistry. Due to the large diversity of these compounds, there is no "single" analytical instrument or method that can be used to study all of them. Furthermore, most of the volatile compounds can be collected only in low concentrations. Therefore, their detection, identification and structural characterization are challenging tasks. The review briefly describes the extraction and preparation methods of samples, then introduces the tools of instrumental analysis utilized to identify or quantify the VOCs of natural products, including spectroscopic and mass spectrometric methods, such as offline GC-MS, multi-dimensional GC-MS, and online approaches including PTR-MS, SIFT-MS, SEMI-MS, DART-MS etc. The current challenges of analytical techniques and future directions are also briefly discussed.
Solid Phase Microextraction (SPME) is a flexible and convenient sampling and sample preparation technique that extracts different kinds of analytes, including both volatile and non-volatile, without the use of a solvent. The technique facilitates fast, simple and automated determination of target analytes in a range of matrices. As it offers a green methodology, it is growing in popularity as an alternative tool in analytical chemistry to traditional methods. This book follows on in spirit from the editors’ previous title, Applications of Solid Phase Microextraction and will introduce the reader to breakthrough methodologies and cutting edge applications. Although it assumes a good degree of SPME knowledge, an overview of the fundamentals is given before taking the reader through an update of the field.
The reader will learn the basic principles and advantages of different SPME formats including the stir bar extraction techniques, thin film SPME, Bio-SPME, and new trends in different coatings. Applications in complex media, including food analysis, drug residues and bioanalysis are covered.
Bringing together leading sample preparation academics from around the world, the editor has put together an informative new book, suitable for analytical chemists and practitioners utilising SPME tools in their research.
Full evaporative vacuum extraction (FEVE) was developed in this work for analysis of a broad range of semivolatile organic compounds (SVOCs) in drinking water and surface water. Sorbent pens are used in a two-stage process that first evaporates the sample matrix through sorbent beds under vacuum to recover the lighter SVOCs, followed by the application of a higher temperature and stronger vacuum to the sample vial to recover the remaining heavier SVOCs once the matrix has evaporated. After extraction, the sorbent pens are desorbed into a GC-MS using a uniquely designed "splitless" delivery system to maximize sensitivity. Critical extraction and desorption parameters that affect the method performance were optimized. After FEVE, the sorbent pens can be stored for 7-10 days at room temperature while maintaining a less than 15% loss in analyte recovery. As a proof of concept, 10 drinking water and surface water samples were analyzed using this method. 69 analytes were detected in these water samples, with the highest concentration of 1986 ng/L for bromacil. Heptachlor epoxide, chlorpyrifos, metolachlor, butachlor, and 2,3',4',5-tetrachlorobiphenyl were detected in four samples. None of the analytes were above the health and safety thresholds set by California Proposition 65.
A fluorinated covalent organic framework (COF), named F-COF, was fabricated via simple room-temperature synthesis. With the characteristics of rich fluorine atoms, hydrophobicity, and large conjugated structure, F-COF was evaluated for the extraction of five benzoylurea insecticides (BUs) containing fluorine atoms, benzene ring, and urea bridge. Specifically, F-COF-coated stir bars were prepared by physical adhesion and exhibited higher extraction recovery (73-93 versus 40-85%) toward BUs than commercial stir bars in a shorter extraction time (50 min versus 24 h). The adsorption behavior of BUs on F-COF was explored, and it was assumed that the halogen bond (O-F), hydrophobic interaction, electrostatic interaction, and π-π stacking contributed to the adsorption. On the basis of it, a method combining stir bar sorptive extraction with liquid chromatography-ultraviolet detector was developed for trace analysis of five BUs. Under the optimal conditions, the limits of detection for BUs were found to be 0.301-0.672 μg/L, with the linear range of 1.0/2.0-500 μg/L and relative standard deviations of <8.0% (c = 5 μg/L and n = 7). The accuracy of the proposed method was validated by the recovery test, and the recoveries of target BUs in spiked pear juice and pear beverage were 82.0-113 and 84.0-112%, respectively.
This study evaluated the effects of in-the-bag dry-ageing on eating quality and volatile compounds of longissimus lumborum from cows and steers. Compared to wet-ageing, in-the-bag dry-ageing increased purge loss (P < 0.0001), cooking time (P < 0.0001), salty taste (P < 0.05) and sour-dairy flavour (P < 0.01), whereas decreased cooking loss (P < 0.0001), amount of perceptible connective tissue (P < 0.05) and livery flavour (P < 0.05) in both cow and steer meat. This dry-ageing technology also increased juiciness (P < 0.01) and brown-roasted aroma (P < 0.05) in steer meat, whereas decreased the juiciness (P < 0.01) of cow meat. Regardless of the ageing method, cow meat was tougher (P < 0.0001), less juicy (P < 0.001) and sweeter (P < 0.05) and presented higher amount of perceived connective tissue (P < 0.0001) than steer meat, whereas steer meat had higher ratings for beef (P < 0.05) and brown-roasted (P < 0.01) flavours. Volatile compounds were largely affected (P < 0.05) by animal-type, most of them being higher in cow than steer meat. In contrast, in-the-bag dry-ageing did not extensively affect the volatile profile, only a few alcohols, aldehydes and ketones.
The monitoring of food contaminants is of interests to both food regulatory bodies and the consumers. This literature review covers polycyclic aromatic hydrocarbons (PAHs) with regard to their background, sources of exposures, and occurrence in food and environment as well as health hazards. Furthermore, analytical methods focusing on the analysis of PAHs in tea, coffee, milk, and alcoholic samples for the last 16 years are presented. Numerous experimental methods have been developed aiming to obtain better limits of detections (LODs) and percent recoveries as well as to reduce solvent consumption and laborious work. These include information such as the selected PAHs analyzed, food matrix of PAHs, methods of extraction, cleanup procedure, LOD, limits of quantitation (LOQ), and percent recovery. For the analysis of tea, coffee, milk, and alcoholic samples, a majority of the research papers focused on the 16 US Environmental Protection Agency PAHs, while PAH4, PAH8, and methylated PAHs were also of interests. Extraction methods range from the classic Soxhlet extraction and liquid–liquid extraction to newer methods such as QuEChERS, dispersive solid-phase microextraction, and magnetic solid-phase extraction. The cleanup methods involved mainly the use of column chromatography and SPE filled with either silica or Florisil adsorbents. Gas chromatography and liquid chromatography coupled with mass spectrometry or fluorescence detectors are the main analytical instruments used. A majority of the selected combined methods used are able to achieve LODs and percent recoveries in the ranges of 0.01–5 ug/kg and 70–110%, respectively, for the analysis of tea, coffee, milk, and alcoholic samples.
This study aims to extract and characterize cellulose nanocrystals (CNCs) from date pits (DP), an agricultural solid waste. Two methods were used and optimized for the cellulose nanocrystals (CNCs) extraction, namely the mechanical stirrer method (CNCs1) and the Soxhlet apparatus method (CNCs2) in terms of chemical used, cost, and energy consumption. The results showed that scanning electron microscopy revealed the difference in the morphology as they exhibit rough surfaces with irregular morphologies due to the strong chemical treatments during the delignification and bleaching process. Moreover, transmission electron microscopy analysis for CNCs reveals the true modification that was made through sulfuric acid hydrolysis as it presents cellulose microfibrils with a packed structure. Fourier transform infrared proved that the CNCs were successfully extracted using the two methods since most of the lignin and hemicellulose components were removed. The crystallinity index of CNCs1 and CNCs2 was 69.99%, and 67.79%, respectively, and both presented a high yield of CNCs (≥ 10%). Ultimately, both techniques were successful at extracting CNCs. Based on their cost-effectiveness and time consumption, it was concluded that method 1 was less expensive than method 2 based on the breakdown of the cost of each step for CNCs production.
In this study, spherical imine-linked covalent organic frameworks (COFs) were fabricated from 2,5-dimethoxybenzene-1,4-dialdehyde (DMTP) and 1,3,5-tris (4-aminophenyl) benzene (TAPB) and named as TAPB-DMTP-COFs. The resulting powders were coated onto bare glass bars via physical-adhesion to obtain TAPB-DMTP-COFs coated stir bars. The self-made stir bars exhibited higher extraction efficiency (74-85%) and faster dynamics (50 min) towards non-steroidal anti-inflammatory drugs (NSAIDs) over ethylene glycol-Silicone (42-68%, 180 min) and polydimethylsiloxane (3-61%, 180 min) coated stir bars. Fourier transform infrared (FT-IR) spectra, X-ray photoelectron spectroscopy (XPS), zeta potential and water contact angle were employed to provide a comprehensive understanding of the adsorption mechanism between the coating and analytes. The results displayed that methoxy group worked as an adsorption site helping the adsorption of interest NSAIDs onto the TAPB-DMTP-COFs coating and hydrogen bonds formed between the O atoms and the analytes. Additionally, the adsorption mechanisms possibly also involved π-π interaction and hydrophobic interaction. Moreover, TAPB-DMTP-COFs coated stir bars exhibited good stability and could be reused more than 60 times. Subsequently, a method by combining TAPB-DMTP-COFs coated stir bar sorptive extraction (SBSE) with liquid chromatography (HPLC)-ultraviolet detector (UV) was established for the determination of four NSAIDs in environmental waters. Under the optimized conditions, the established method showed a wide linear range of 0.2/1-500 μg/L for interest NSAIDs, the limits of detection varied from 0.039 to 0.312 μg/L. Yangtze River water, East Lake water and Spring water were subjected to the proposed method, the recoveries in spiked samples were 84.7-104%, 81.2-101% and 82.6-97.6%, respectively.
This review article compares and contrasts sample preparation techniques coupled with high-performance liquid chromatography (HPLC) and describes applications developed in biomedical, forensics, and environmental/industrial hygiene in the last two decades. The proper sample preparation technique can offer valued data for a targeted application when coupled to HPLC and a suitable detector. Improvements in sample preparation techniques in the last two decades have resulted in efficient extraction, cleanup, and preconcentration in a single step, thus providing a pathway to tackle complex matrix applications. Applications such as biological therapeutics, proteomics, lipidomics, metabolomics, environmental/industrial hygiene, forensics, glycan cleanup, etc., have been significantly enhanced due to improved sample preparation techniques. This review looks at the early sample preparation techniques. Further, it describes eight sample preparation technique coupled to HPLC that has gained prominence in the last two decades. They are (1) solid-phase extraction (SPE), (2) liquid-liquid extraction (LLE), (3) gel permeation chromatography (GPC), (4) Quick Easy Cheap Effective Rugged, Safe (QuEChERS), (5) solid-phase microextraction (SPME), (6) ultrasonic-assisted solvent extraction (UASE), and (7) microwave-assisted solvent extraction (MWASE). SPE, LLE, GPC, QuEChERS, and SPME can be used offline and online with HPLC. UASE and MWASE can be used offline with HPLC but have also been combined with the online automated techniques of SPE, LLE, GPC, or QuEChERS for targeted analysis. Three application areas of biomedical, forensics, and environmental/industrial hygiene are reviewed for the eight sample preparation techniques. Three hundred and twenty references on the eight sample preparation techniques published over the last two decades (2001-2021) are provided. Other older references were included to illustrate the historical development of sample preparation techniques.
In this work, novel dummy molecularly imprinted membranes (MIMs) were fabricated using the nylon-66 (NY-66) membranes as the subtracts based on an eco-friendly “sandwich” technology with less consumption of organic reagents at mild conditions for recognition and extraction of enrofloxacin (ENR) and ciprofloxacin (CIP) in egg samples. The prepared MIMs were characterized by SEM, ATR-FTIR and TGA, showing the successful construction of uniform and porous polymers on the surface of membranes. A series of adsorption affinity tests were investigated, indicating the prepared materials had specific recognition capacity and excellent stability as novel sorbents. Furthermore, Box-Benhnken design (BBD) and single factor investigations were applied to optimize pretreatment procedures, coupling with Ultra High Performance Liquid Chromatograph (UHPLC) detection. The method showed a good correlation (r²>0.9999) within the linear range of 5.0∼5000.0 µg kg⁻¹, and limit of detection (LOD) of ENR and CIP were 0.3 and 0.7 µg kg⁻¹, respectively. The mean recovery ranged from 84.5% to 97.0% within relative standard deviations (RSDs) of 10.2%. Finally, ENR and CIP were not detected in 3 batches of egg samples. The current study developed the dummy MIMs as sorbents combined with UHPLC analysis for extraction and detection of target analytes in food matrices.
随着绿色化学的发展,开发和应用符合绿色化学要求的溶剂和方法备受关注。作为离子液体类似物,低共熔溶剂(deep eutectic solvent, DES)是通过氢键受体(hydrogen bond acceptor, HBA)和氢键供体(hydrogen bond donator, HBD)的氢键作用而形成的一种混合物,具有环境友好、制备简单、成本低、可生物降解等优点,在很多领域均有越来越广泛的应用。DES可以从不同样品中萃取和分离不同的目标化合物,其作为萃取溶剂具有独特的优势,可以获得较高的萃取效率且样品基质对分析过程的影响较小。在分散液液微萃取(dispersive liquid-liquid micro-extraction, DLLME)程序中,DES可以萃取复杂基质中的残留药物、金属离子和生物活性成分;与传统的萃取方法相比,该方法具有对有机试剂需求少,萃取效率更高等明显优势。而且,在DLLME中加入DES作为分散剂,能够加速萃取剂在样品溶液中的扩散,具有小型化、成本低等优点。相比于传统分散剂甲醇、乙腈的高挥发性、易燃性,DES的高稳定性、低毒性使其在绿色化学领域中更具有优势,应用更广。因此,DES与DLLME的结合近年来发展迅速。不仅如此,DES与固相萃取联合应用也具有广泛的应用前景,在与固相萃取小柱和搅拌棒联合应用时,DES可以作为洗脱剂,氢键供体及氢键给体的用量之比是洗脱效率的重要考察因素之一。在与磁性材料联用时,DES能与磁性多壁碳纳米管、磁性氧化石墨烯等纳米复合材料结合,通过氢键、π-π作用力和静电作用力等特异性吸附目标分析物。并且能够参与磁性凝胶和分子印迹聚合物的合成,推动磁性材料向绿色化学的方向发展,进一步拓展DES的应用。作为一类新兴的绿色溶剂,DES在化合物的萃取分离技术方面受到广泛关注,在不同的萃取技术中扮演了不同的角色,并表现出良好的性能,因此逐渐成为绿色化学领域的研究重点。该文整合了DES在萃取分离技术中的研究进展,介绍了DES的制备、性质和分类,对DES在DLLME和固相萃取中的应用进行了总结和归类,并展望了DES在萃取分离技术中的应用前景,为DES未来的应用提供参考。
Preparation of the biological samples is one of the most critical steps in sample analysis. In past decades, the liquid–liquid extraction technique has been used to extract the desired analytes from complex biological matrices. However, solid-phase extraction (SPE) gained popularity due to versatility, simplicity, selectivity, reproducibility, high sample recovery %, solvent economy, and time-saving nature. The superior extraction efficiency of SPE can be attributed to the development of advanced techniques, including the nanosorbents technology. The nanosorbent technology significantly simplified the sample preparation, improved the selectivity, diversified the application, and accelerated the sample analysis. This review critically expands on the to-date advancements reported in SPE with particular regards to the nanosorbent technology.
The 12 pyrethroid Pesticides residues in tea samples can be rapidly extracted and separated by a noval stir bar sorptive extraction(SBSE)-thermal desorption(TDU)-gas chromatography(GC) method. Impurities and pyrethroid pesticides residues of tea can be seperated by this method.and then use TDU-GC to analyse pyrethroid Pesticides residues. The residues of 12 pyrethroid pesticides at same time can be identified and quantified simultaneously by SBSE-TDU-GC rapidiy with high sensitivity and good reproducibility. This method is simple, rapid, and the average adding standard recovery ratios were 92.89%-105.01%.The correlation coefficient of pyrethroid pesticides in tea samples is >0.9926. Good repeatability(n=6) was obtained in all the cases with The relative standard deviation lower 9.7%.Pyrethroid pesticides residues in 4 real tea samples can be determined rapidly by this method, their pyrethroid pesticide residues are all less than MRL of China and European union.
A stir bar sorptive extraction gas chromatography–mass spectrometry (SBSE–GC–MS) method has been used for the characterization of the volatile composition of 26 high quality vinegars of three different protected geographical indications (traditional balsamic vinegar of Modena, balsamic vinegar of Modena, and Sherry vinegar). SBSE technique provided the identification of 113 volatile compounds, which belong to different chemical families (short-chain esters, acids, acetates and alcohols, phenols, lactones and benzenic and furanic compounds). 39 volatile compounds were never previously reported in wine vinegars. This characterization contributed to the differentiation of the 100% of the studied samples on the basis of raw material (two different types of wine, and cooked must), aging type (static and dynamic) and aging time (<5 years, between 5 and 25 years, and >25 years). Furanes and terpenes together with acids and alkanes were the most discriminant variables for raw material and aging time, respectively, whereas for aging type, these ones were acetates and esters.
In this report, an automated method for sorptive enrichment of aqueous samples is presented. It is based on sorption of the analytes of interest into a packed bed containing 100% polydimethylsiloxane (PDMS) particles followed by thermal desorption for complete transfer of the enriched solutes onto the GC column. Compared to other solvent-less sample preparation techniques for water samples, several improvements can be noted of which the most obvious are an enhanced sensitivity and improved blanks. Moreover, degradation products formed from the PDMS material can easily be identified with the use of a mass spectrometric detector. As these products contain silicone, they do not interfere with the target solutes (pesticides, PAHs). In this report a theory model is derived which allows calculation of breakthrough volumes from octanol–water partitioning coefficients (KO/W). Alternatively, the KO/W value required for complete retention can be calculated using only the sample volume and trap specific parameters. For a sample volume of 10 ml, theory predicts a required log KO/W of 1.77 for the trap used here which was found to be in good agreement with experimental results. For the most apolar solutes, with a log KO/W in excess of seven, poor recoveries were found. This is most likely due to adsorption of these apolar solutes in the system. With the current set-up, detection limits are in the order of 10 ng/l using mass spectrometric detection in the full scan mode.
Molecular Imprinting Technology (MIT) is a technique to design artificial receptors with a predetermined selectivity and specificity for a given analyte, which can be used as ideal materials in various application fields. Molecularly Imprinted Polymers (MIPs), the polymeric matrices obtained using the imprinting technology, are robust molecular recognition elements able to mimic natural recognition entities, such as antibodies and biological receptors, useful to separate and analyze complicated samples such as biological fluids and environmental samples. The scope of this review is to provide a general overview on MIPs field discussing first general aspects in MIP preparation and then dealing with various application aspects. This review aims to outline the molecularly imprinted process and present a summary of principal application fields of molecularly imprinted polymers, focusing on chemical sensing, separation science, drug delivery and catalysis. Some significant aspects about preparation and application of the molecular imprinting polymers with examples taken from the recent literature will be discussed. Theoretical and experimental parameters for MIPs design in terms of the interaction between template and polymer functionalities will be considered and synthesis methods for the improvement of MIP recognition properties will also be presented.
The theory and practice of a novel approach for sample enrichment, namely the application of stir bars coated with the sorbent polydimethylsiloxane (PDMS) and referred to as stir bar sorptive extraction (SBSE) are presented. Stir bars with a length of 10 and 40 mm coated with 55 and 219 μL of PDMS liquid phase, respectively were applied. The 10-mm stir bars are best suited for stirring sample volumes from 10 up to 50 mL whereas 40-mm stir bars are more ideal for sample volumes up to 250 mL. Depending on sample volume and the stirring speed, typical stirring times for equilibration are between 30 and 60 min. The performance of SBSE is illustrated with the analysis of volatile and semivolatile micropollutants from aqueous samples. Detection limits using mass selective detection are in the low ng/L range for a wide selection of analytes from the EPA priority pollutant lists including analytes ranging in volatility from 1,1,1-trichloroethane to chrysene. For the extraction of selected compounds from 200-mL samples, detection limits below 0.1 ng/L are reached in the selected ion monitoring mode. A comparison between SBSE and solid-phase microextraction is made. ©1999 John Wiley & Sons, Inc. J Micro Sep 11: 737–747, 1999
http://dx.doi.org/10.1021/bk-2001-0791
TABLE OF CONTENTS
preface
Overview
1. Pharmaceuticals and Personal Care Products in the Environment: Overarching Issues and Overview, Christian G. Daughton
2. Pharmaceuticals and Metabolites as Contaminants of the Aquatic Environment, Thomas Ternes
Occurrence in the Environment
3. Occurrence and Fate of Fluoroquinolone, Macrolide, and Sulfonamide Antibiotics during Wastewater Treatment and in Ambient Waters in Switzerland, Alfredo C. Alder, et al.
4. Occurrence of Pharmaceutical Residues in Sewage, River, Ground, and Drinking Water in Greece and Berlin (Germany), Th. Heberer, et al.
5. Pharmaceuticals in Groundwater: Clofibric Acid beneath Sewage Farms South of Berlin, Germany, Traugott Scheytt, et al.
6. Phenazone Analgesics in Soil and Groundwater below a Municipal Solid Waste Landfill, Marijan Ahel and Ivana Jelidcid'c
7. Pharmaceuticals and Personal Care Products in the Waters of Lake Mead, Nevada
Personal Care Products
8. Occurrence and Fate of Synthetic Musks in the Aquatic System of Urban Areas: Polycyclic and Nitro Musks as Environmental Pollutants in Surface Waters, Sediments, and Aquatic Biota, Th. Heberer, A. These, and U.A. Grosch
9. Ecotoxicology of Musks, D.R. Dietrich and Y. -J. Chou
10. Environmental Risks of Musk Fragrance Ingredients, Froukje Balk, Han Blok, and Daniel Salvito
Waste Treatment
11. Drugs in Municipal Sewage Effluents: Screening and Biodegradation Studies, Edda Md"ohle and Jd"org W. Metzger
12. Concerns about Pharmaceuticals in Water Reuse, Groundwater Recharge, and Animal Waste, Jd"org E. Drewes and Laurence S. Shore
Ecotoxicological Issues
13. Iodinated X-ray Contrast Media in the Aquatic Environment: Fate and Effects, T. Steger-Hartmann, R. Ld"ange, and H. Schweinfurth
14. Multidrug-Multienobiotic Transporters and Their Significance with Respect to Environmental Levels of Pharmaceuticals and Personal Care Products, D. Epel and T. Smital
15. Antidepressants in Aquatic Organisms: A Wide Range of Effects, Peter P. Fong
16. Veterinary Medicines and Soil Quality: The Danish Situation as an Example, John Jensen
Risk Assessment
17. Environmental Risk Assessment of Pharmaceuticals: A Proposal with Special Emphasis on European Aspects, Jd"org Rd"ombke, Thomas Knacker, and Hanka Teichmann
18. Regulatory Oversight for the Environmental Assessment of Human and Animal Health Drugs: Environmental Assessment Regulations for Drugs, Ranga Velagaleti and Michael Gill
19. Degradation and Depletion of Pharmaceuticals in the Environment, Ranga Velagaleti and Michael Gill
Epilog: Linkage between Social Sciences and Environmental Monitoring
20. Illicit Drugs in Municipal Sewage: Proposed New Nonintrusive Tool to Heighten Public Awareness of Societal Use of Illicit-Abused Drugs and Their Potential for Ecological Consequences, Christian G. Daughton
Author Index
Subject Index
The sol-gel process allows the fabrication of a wide range of material systems with differences in size, shape, charge, porosity, polarity, etc. These resulting materials possess high purity and material homogeneity that attract applications in various scientific fields including analytical microextraction, which is the focus of this chapter. No one material is appropriate for all extractions; hence, materials are constantly being developed and modified to bring about more selective and efficient extraction. Sampling and sample preparation are responsible for the greater portion of the global uncertainty of an analytical procedure which warrants further development and research in this important field. In conventional analytical protocol, sampling, sample preparation, and sample introduction are treated separately; this increases the chance of losing analyte, reduces repeatability, and hampers automation. Sol-gel technology provides a straightforward pathway to achieving stable performance, procedural simplification, the creation of efficient extraction media, enhanced reproducibility, and ease in automation of various microextraction schemes. This chapter will convey, in general terms, the usefulness of sol-gel technology and, in specific terms, its application in preparing sorbents for extracting a wide range of analytes in the environment, food, biomedical fields, etc., with the main focus being their application in SPME, CME, and SBSE. Also, the sol-gel process will be explained and instructions given on how to use it to prepare certain microextraction devices. Additionally, a detailed account will be provided on how to prepare and characterize sol-gel materials and how to couple the sol-gel microextraction techniques with various chromatographic and electrophoretic separation instruments.
This chapter provides a detailed procedure for performing automated binding studies properly. Protocol for automated high-throughput SPME-LC using the Concept 96 Robotic Sample Preparation Station describes a generalized sample preparation procedure using automated solid-phase microextraction (SPME) or thin-film microextraction (TFME) and the Concept 96 robotic station for the extraction of target compounds from a complex biofluid, tissue homogenate, or any other complex matrix of interest. The objective of protocol for automation of ligand-receptor binding studies using Concept 96 is to provide a procedure to perform such automated ligand-receptor binding studies. The experimental design described herein uses the method of multiple standard solutions where ligand is spiked directly into the receptor solution, because this type of design allows an increase in throughput by performing assay in parallel using the multi-well plate format and Concept 96. In Vivo SPME Protocol for Direct Monitoring of Circulating Intravenous Blood Concentrations describes the main steps of an in vivo SPME procedure that can be used to monitor intravenous concentrations of drugs and metabolites in beagles or other large animals without needing to withdraw a blood sample for analysis. The use of in vivo SPME for direct extraction of analytes from blood or tissue eliminates the need for blood withdrawal and offers numerous advantages. Protocol for Setting up Automated SPME-GC Methods can be used for fast and automated SPME method development as well as to carry out automated and high-throughput SPME-GC analyses. Example applications include both targeted and global analyses in fields such as environmental analysis, food chemistry, bioanalysis, industrial hygiene, and metabolomics.
Parabens is the name given to a group of p-hydroxybenzoic acid (PHBA) esters used in over 22,000 cosmetics as preservatives at concentrations up to 0.8% (mixtures of parabens) or up to 0.4% (single paraben). The group includes Methylparaben, Ethylparaben, Propylparaben, Isopropylparaben, Butylparaben, Isobutylparaben, and Benzylparaben. Industry estimates of the daily use of cosmetic products that may contain parabens were 17.76 g for adults and 378 mg for infants. Parabens in cosmetic formulations applied to skin penetrate the stratum corneum in inverse relation to the ester chain length. Carboxylesterases hydrolyze parabens in the skin. Parabens do not accumulate in the body. Serum concentrations of parabens, even after intravenous administration, quickly decline and remain low. Acute toxicity studies in animals indicate that parabens are not significantly toxic by various routes of administration. Subchronic and chronic oral studies indicate that parabens are practically nontoxic. Numerous genotoxicity studies, including Ames testing, dominant lethal assay, host-mediated assay, and cytogenic assays, indicate that the Parabens are generally nonmutagenic, although Ethylparaben and Methylparaben did increase chromosomal aberrations in a Chinese Hamster ovary cell assay. Ethylparaben, Propylparaben, and Butylparaben in the diet produced cell proliferation in the forestomach of rats, with the activity directly related to chain length of the alkyl chain, but Isobutylparaben and Butylparaben were noncarcinogenic in a mouse chronic feeding study. Methylparaben was noncarcinogenic when injected subcutaneously in mice or rats, or when administered intravaginally in rats, and was not cocarcinogenic when injected subcutaneously in mice. Propylparaben was noncarcinogenic in a study of transplacental carcinogenesis. Methylparaben was nonteratogenic in rabbits, rats, mice, and hamsters, and Ethylparaben was nonteratogenic in rats. Parabens, even at levels that produce maternal toxicity, do not produce fetal anomalies in animal studies. Parabens have been extensively studied to evaluate male reproductive toxicity. In one in vitro study, sperm were not viabile at concentrations as low as 6 mg/ml Methylparaben, 8 mg/ml Ethylparaben, 3 mg/ml Propylparaben, or 1 mg/ml Butylparaben, but an in vivo study of 0.1% or 1.0% Methylparaben or Ethylparaben in the diet of mice reported no spermatotoxic effects. Propylparaben did affect sperm counts at all levels from 0.01% to 1.0%. Epididymis and seminal vesicle weight decreases were reported in rats given a 1% oral Butylparaben dose; and decreased sperm number and motile activity in F1 offspring of rats maternally exposed to 100 mg/kg day- 1 were reported. Decreased sperm numbers and activity were reported in F1 offspring of female rats given Butylparaben (in DMSO) by subcutaneous injection at 100 or 200 mg/kg day- 1, but there were no abnormalities in the reproductive organs. Methylparaben was studied using rats at levels in the diet up to an estimated mean dose of 1141.1 mg/kg day- 1 with no adverse testicular effects. Butylparaben was studied using rats at levels in the diet up to an estimated mean dose of 1087.6 mg/kg day- 1 in a repeat of the study noted above, but using a larger number of animals and a staging analysis of testicular effects - no adverse reproductive effects were found. Butylparaben does bind to estrogen receptors in isolated rat uteri, but with an affinity orders of magnitude less than natural estradiol. Relative binding (diethylstilbesterol binding affinity set at 100) to the human estrogen receptors α and β increases as a function of chain length from not detectable for Methylparaben to 0.267 ± 0.027 for human estrogen receptor α and 0.340 ± 0.031 for human estrogen receptor β for Isobutylparaben. In a study of androgen receptor binding, Propylparaben exhibited weak competitive binding, but Methylparaben had no binding effect at all. PHBA at 5 mg/kg day-1 subcutaneously (s.c.) was reported to produce an estrogenic response in one uterotrophic assay using mice, but there was no response in another study using rats (s.c. up to 5 mg/kg day- 1) and mice (s.c. up to 100 mg/kg day- 1) and in a study using rats (s.c. up to 100 mg/kg day- 1). Methylparaben failed to produce any effect in uterotrophic assays in two laboratories, but did produce an effect in other studies from another laboratory. The potency of Methylparaben was at least 1000× less when compared to natural estradiol. The same pattern was reported for Ethylparaben, Propylparaben, and Butylparaben when potency was compared to natural estradiol. In two studies, Isobutylparaben did produce an estrogenic response in the uterotrophic assay, but the potency was at least 240,000× less than estradiol. In one study, Benzylparaben produced an estrogenic response in the uterotrophic assay, but the potency was at least 330,000× less than estradiol. Estrogenic activity of parabens and PHBA was increased in human breast cancer cells in vitro, but the increases were around 4 orders of magnitude less than that produced by estradiol. Parabens are practically nonirritating and nonsensitizing in the population with normal skin. Paraben sensitization has occurred and continues to be reported in the case literature, but principally when exposure involves damaged or broken skin. Even when patients with chronic dermatitis are patch-tested to a parabens mix, parabens generally induce sensitization in less than 4% of such individuals. Many patients sensitized to paraben-containing medications can wear cosmetics containing these ingredients with no adverse effects. Clinical patch testing data available over the past 20 years demonstrate no significant change in the overall portion of dermatitis patients that test positive for parabens. As reviewed by the Cosmetic Ingredient Review (CIR) Expert Panel, the available acute, subchronic, and chronic toxicity tests, using a range of exposure routes, demonstrate a low order of parabens' toxicity at concentrations that would be used in cosmetics. Parabens are rarely irritating or sensitizing to normal human skin at concentrations used in cosmetics. Although parabens do penetrate the stratum corneum, metabolism of parabens takes place within viable skin, which is likely to result in only 1% unmetabolized parabens available for absorption into the body. The Expert Panel did consider data in the category of endocrine disruption, including male reproductive toxicity and various estrogenic activity studies. The CIR Expert Panel compared exposures to parabens resulting from use of cosmetic products to a no observed adverse effect level (NOAEL) of 1000 mg/kg day- 1 based on the most statistically powerful and well-conducted study of the effects of Butylparabens on the male reproductive system. The CIR Expert Panel considered exposures to cosmetic products containing a single parabens preservative (use level of 0.4%) separately from products containing multiple parabens (use level of 0.8%) and infant exposures separately from adult exposures in determining margins of safety (MOS). The MOS for infants ranged from ∼6000 for single paraben products to ∼3000 for multiple paraben products. The MOS for adults ranged from 1690 for single paraben products to 840 for multiple paraben products. The Expert Panel considers that these MOS determinations are conservative and likely represent an overestimate of the possibility of an adverse effect (e.g., use concentrations may be lower, penetration may be less) and support the safety of cosmetic products in which parabens preservatives are used.
The current rapid development of green analytical chemistry (GAC) requires clear, concise guidelines in
the form of GAC principles that will be helpful in greening laboratory practices. The existing principles of
green chemistry and green engineering need revision for their use in GAC because they do not fully meet
the needs of analytical chemistry.
In this article we propose a set of 12 principles consisting of known concepts (i.e. reduction in the use of
reagents and energy, and elimination of waste, risk and hazard) together with some new ideas (i.e. the
use of natural reagents), which will be important for the future of GAC.
Stir-bar sorptive extraction (SBSE) is a sample-preparation technique that allows the sorptive extraction and preconcentration of emerging organic contaminants (EOCs) from complex matrices. Since its introduction, this technique has been widely applied in environmental, food and biological research, followed by gas chromatography (GC) or liquid chromatography (LC). However, the single commercially available coating for SBSE, based on polydimethylsiloxane, has become its principal limitation, so use of SBSE has been reduced to the extraction of apolar or moderately polar compounds. In recent years, there has been growing interest in developing more polar in-house coatings for SBSE. Different approaches to synthesis of polar coatings for SBSE have been developed, with sol-gel technology and monolithic materials being notable examples. This review focuses on the commonest and novel strategies for synthesizing new coatings for SBSE to enhance the extraction of polar EOCs and their applications.
Since its introduction in 1990s, different configurations of solid-phase microextraction (SPME) have been evaluated for different applications, and can be classified into the static and dynamic techniques. The current review briefly discusses the development of the techniques applied to reduce extraction time and/or to enhance extraction efficiency. It is also reviews selective microextraction techniques, such as molecularly-imprinted polymer, immunoaffinity, restricted access material and aptamer sol-gel SPME.
This paper reports the application of a chiral imprinted polymer (CIP)-coated stir bar for the selective extraction of (+)-(S)-citalopram (SCIT) and its main metabolites, (+)-(S)-desmethylcitalopram (SDCIT) and (+)-(S)-didesmethylcitalopram (SDDCIT), from urine samples. The developed device has been demonstrated to be capable of selectively extracting the three target analytes from urine samples without saturating the imprinted sites. A CIP-coated stir bar sorptive extraction procedure (CIP-SBSE) is proposed for the isolation of SCIT, SDCIT and SDDCIT followed by their subsequent analysis using liquid chromatography ion trap mass spectrometry (LC-ITMS). Deuterated SCIT-d6 was used as an internal standard. The method was validated using a standard procedure, which revealed that a quantification of 5ngmL(-1) was obtained in urine samples and that the accuracy and precision were within the established values while no matrix effect was observed.
Trimethoprim molecularly imprinted polymer (MIP) was prepared as the coating of stir bar sorptive extraction (SBSE) and applied to the trace analysis of trimethoprim and three sulfonamides in complex samples. The MIP-coating was about 21.5 μm thickness with the relative standard deviations (RSD) of 5.9% (n = 10). It was homogeneous and dense with good thermal and chemical stability. The extraction capability of the MIP-coating was 1.7 times over that of the non-imprinted polymer (NIP) coating. The MIP-coating exhibited selective adsorption ability to sulfonamides, triazines and methotrexate besides antibacterial synergists. The methods for the determination of trimethoprim and three sulfonamides by MIP-coated stir bar sorptive extraction coupled with HPLC were developed. It was successfully applied to the trace trimethoprim analysis in spiked urine and plasma samples. The linear range was 5-200 μg L−1 and the detection limit was 1.6 μg L−1. The recoveries in urine and plasma samples were 84.5% to 91.7% with RSDs of 2.9%–4.4%, 71.9% to 85.1% with RSDs of 3.0%–7.3%, respectively. The trimethoprim MIP-coated stir bar was also applied to the trace sulfonamides analysis in spiked milk sample. The linear range was 10–200 μg L−1, the detection limit was within the range of 4.5–6.1 μg L−1, and the recovery was 83.2%–110.2% with RSDs of 4.1%–8.0%.
Ractopamine (RAC) was observed to quench the electrochemiluminescence (ECL) of Ru(bpy)32+–DBAE system at a glassy carbon electrode (GCE). Based on the ECL signal changes, a detection method for RAC in pork was established. Under the optimized conditions, the linear range is from 1.0 × 10−10 to 5.0 × 10−8 mol L−1, and the detection limit is 3.5 × 10−12 mol L−1, which are better than other previously reported methods. Molecularly imprinted polymer (MIP) was synthesized as coating of the stir bar sorptive extraction (SBSE), and MISBSE was used for the selective extraction and purification of RAC in real samples. The ECL method combined with MISBSE pre-treatment was applied for determination of RAC in pork, and the result was satisfactory with the recoveries being 99.7–115.0% and the RSDs being <5% respectively. A possible mechanism of Ru(bpy)32+–DBAE/RAC system was proposed based on UV absorption spectra, cyclic voltammograms and IECL–E curves.
As reproducible coating of stir bars with more polar phases was found to be very difficult, a supporting grid was used in the development of an ethyleneglycol-modified Silicone (EG Silicone) coated stir bar. This new polar coating showed good performance for the extraction of polar solutes, but long term use also showed degradation of the coating due to friction while stirring. In order to address the lower robustness of the EG Silicone stir bar which has a much softer coating compared to a conventional polydimethylsiloxane (PDMS) stir bar, a novel SBSE procedure termed multi-SBSE ((m)SBSE) was developed. (m)SBSE consists of the robust PDMS stir bar stirring at the bottom of the vial and the EG Silicone stir bar attached on the inner side wall of the vial (a magnetic clip is used for the set-up). After extraction, the two stir bars are placed in a single glass desorption liner and are simultaneously thermally desorbed. The desorbed compounds were analyzed by thermal desorption-gas chromatography-mass spectrometry (TD-GC-MS). Compared to conventional SBSE, (m)SBSE provides more uniform enrichment of a wide range of odor compounds in aqueous sample since both stir bars can complement each other, while eliminating the damage of the EG Silicone phase during the extraction. The robustness of the EG Silicone stir bar was dramatically increased and more than 30 extraction and desorption cycles were possible without loss in performance. The recoveries for polar solutes such as 2-acetyl pyrrole (logKow: 0.55), benzyl alcohol (logKow: 1.08), guaiacol (logKow: 1.34), and indole (logKow: 2.05) were increased by a factor of about 2-7. The (m)SBSE-TD-GC-MS method showed good linearity (r(2)>0.9913) and high sensitivity (limit of detection: 0.011-0.071ngmL(-1)) for the test compounds spiked in water. The feasibility and benefit of the method was demonstrated with analysis of odor compounds in roasted green tea. The normalized areas obtained from (m)SBSE showed the best enrichment for most of the selected compounds compared to conventional SBSE using the PDMS stir bar or the EG Silicone stir bar. Fifteen compounds were determined in the range of 0.15-210ngmL(-1) (RSD<14%, n=6).
The new stir-bar coating based on silica gel modified with ketoimine groups was applied to the preconcentration of phenolic endocrine disruptors and heavy metal ions such as Cuii, Criii and Niii in water samples followed by determination using LD-GC/MS and ICP-OES, respectively.
Stir-bar sorptive extraction (SBSE) is a sample-preparation technique that involves extraction and enrichment of organic compounds from a liquid sample. The technique is based on the principle of sorptive extraction. A large amount of an extraction phase (e.g., polydimethyl siloxane) is coated on a stir bar to extract an analyte. The number of studies that have used SBSE has linearly increased in the past 10 years.In this review, we focus on the applications of SBSE to food analysis and novel coating materials.
Recently, haloanisoles and halophenols are associated with multiple product recall situations in the pharmaceutical industry. The majority of the recalls are associated with consumer complaints due to the presence of 2,4,6-tribromoanisole, as extremely low levels of this component can be easily detected by the human nose. As part of the root cause analysis to address the cause of the consumer complaints, a GC–MS/MS based analytical method combined with stir bar sorptive extraction (SBSE) sample preparation was developed for determination of halophenols and haloanisoles from various drug product formulations. The method also applies to the analysis of 2,4,6-tribromoanisole analysis in various packaging materials. The optimized MS/MS method is based on component-specific MRM transitions. The detection limit is component dependent and in the range of 1–100 pg/tablet for solid dosage formulations and 0.04–4 ng/L for water based solutions. Deuterated tribromoanisole was used as internal standard for quantitation. The paper also may provide guidance for performing trace level method validation in the regulated Pharmaceutical Industry.
In this paper, we analysed the volatile and semi-volatile compounds, including E,E-farnesol in Makgeolli which is a traditional type of Korean fermented rice wines. Forty-one compounds including alcohols, 1-butanol-3-methyl acetate, E,E-farnesol, stearol, and phytane, were separated and quantified by dynamic headspace sampling (DHS) and stir bar sorptive extraction (SBSE) coupled with gas chromatography-mass spectrometry. SBSE has been found to be an effective method for analysing E,E-farnesol levels in Makgeolli. The experimental parameters related to the extraction efficiency of the SBSE method, such as ethanol concentration and filtration, were studied and optimised. The linear dynamic range of the SBSE method for E,E-farnesol ranged from 0.02 to 200ngml(-1) with R(2)=0.9974. The limit of detection and limit of quantification of the SBSE method were 0.02 and 0.05ngml(-1), respectively. The relative standard deviation of intra- and inter-day reproducibility was less than 6.2% and 9.9%, respectively.
In this work, three kinds of metal-organic frameworks (MOFs), MOF-5, MOF-199 and IRMOF-3, were introduced in stir bar sorptive extraction (SBSE) and novel polydimethylsiloxane (PDMS)/MOFs (including PDMS/MOF-5, PDMS/MOF-199 and PDMS/IRMOF-3) coated stir bars were prepared by sol-gel technique. These PDMS/MOFs coatings were characterized and critically compared for the extraction of seven target estrogens (17-β-estradiol, dienestrol, diethylstilbestrol, estrone, 4-t-octylphenol, bisphenol-A and 17α-ethynylestradiol) by SBSE, and the results showed that PDMS/IRMOF-3 exhibited highest extraction efficiency. Based on the above facts, a novel method of PDMS/IRMOF-3 coating SBSE-high performance liquid chromatography ultraviolet (HPLC-UV) detection was developed for the determination of seven target estrogens in environmental waters. Several parameters affecting extraction of seven target estrogens by SBSE (PDMS/IRMOF-3) including extraction time, stirring rate, pH, ionic strength, desorption solvent and desorption time were investigated. Under the optimal experimental conditions, the limits of detection (LODs, S/N=3) were found to be in the range of 0.15-0.35μg/L. The linear range was 2-2500μg/L for 17α-ethynylestradiol and 1-2500μg/L for other estrogens. The relative standard deviations (RSDs) were in the range of 3.7-9.9% (n=8, c=20μg/L) and the enrichment factors were from 30.3 to 55.6-fold (theoretical enrichment factor was 100-fold). The proposed method was successfully applied to the analysis of estrogens in environmental water samples, and quantitative recoveries were obtained for the spiking experiments.
A novel dendrimer-based molecularly imprinted polymers (MIPs) coated dumbbell-shaped stir bar (DSB) was developed to enrich and analyse two kinds of phosphodiesterase type 5 (PDE-5) inhibitors in health foods (Hfs). The MIPs, with vardenafil as template molecule and methacrylic acid (MAA) as functional monomer, were synthesized on the surface of the dendritic-grafting DSB which was filled with magnetic core as substrate. The MIPs-DSB possessed mechanical stability, high adsorption capacity and good selectivity for vardenafil and its analogue sildenafil. A method for the determination of vardenafil and sildenafil in Hfs was established by SBSE coupled with HPLC-UV. The contents of vardenafil and sildenafil were found to be 3.65 and 2.66 μg g−1, respectively, and the average recoveries in spiked Hfs were 86.5-91.8% with a relative standard deviation (RSD) below 5%. All results revealed that the MIPs-DSB coupled with HPLC-UV could be applied to the highly selective extraction and sensitive determination of trace analytes in complex matrix.
In this work, a novel molecularly imprinted polymer (MIP) coated stir bar was fabricated and used for the extraction of trace amounts of Cu from drinking water. Cu–morin complex was used as template molecule which was chemically bonded to a glass stir bar and was employed for stir bar sorptive extraction of trace amounts of copper ions. The effects of different parameters such as pH, adsorption and desorption time, stirring rate, temperature and amount of ligand (morin) were evaluated on the extraction efficiency and the optimum conditions were established: the extraction and desorption times were fixed respectively at 20 and 30 min, mole ratio of ligand to the analyte was selected as 2, stirring speed was 700 rpm, pH was adjusted to 5 and the extraction process was performed at a temperature of 45 °C. Under these conditions, a pre-concentration factor of 25 was achieved and the total capacity of the stir bar for copper uptake was found to be 1200 μg. A non-imprinted polymer coating was used for comparison. The MIP stir bar showed sufficient mechanical and chemical stability and was able to perform more than 50 extractions without any damage to the polymer phase. The reproducibility between stir bars (n = 5) was 8.9%. The detection limit of the proposed method was found to be 0.38 μg L−1 with a relative standard deviation within 0.56–5.3% and a dynamic range between 1 and 1000 μg L−1. The method was successfully applied to the pre-concentration and determination of copper in a few different water samples.
A highly sensitive and selective method based on alkaline digestion for the simultaneous determination of bisphenol A (BPA) and 4-nonylphenol (NP) was developed. The method consists of digestion of the matrix with ethanolic KOH, extraction with diethyl ether under a mild alkaline condition, cleaning with successive aminopropyl (NH2) cartridges and derivatization followed by a GC-MS analysis. The assay accuracies, expressed as recoveries, were 82 - 113% for BPA and 89 - 97% for NP. The limits of detection of BPA and NP were 0.09 ng/g and 0.50 ng/g, respectively. The procedure will be reliable for the trace analysis of BPA and NP in human milk, since alkaline digestion can diminish their documented association with protein.
The new technique of stir bar sorptive extraction (SBSE) using stirrers 10mm long coated with 55μl polydimethylsiloxane (PDMS) was used to determine polycyclic aromatic hydrocarbons (PAHs) from water samples. The desorption of the extracted analytes was performed with ultrasonic treatment in autosampler vials with glass flat bottom inserts using 150μl of acetonitrile (ACN) or an ACN–water mixture (4:1) as solvent. The PAHs were determined with column liquid chromatography (LC) and fluorescence detection. The recoveries of the stir bar sorptive extraction for the compounds investigated were between 58% and about 100%, and the detection limits of this method under the given conditions (extraction from a 10ml sample, 1h extraction time and 10min desorption time) were very low (between 0.2 and 2ng/l). The standard deviations (n=5) using five different stirrers at a concentration level of 50ng/l ranged between 4.7 and 13.5%.
Stir bar sorptive extraction followed by liquid desorption and high performance liquid chromatography with tandem mass spectrometry (SBSE-LD-LC-MSMS) has been developed for the determination of 15 pesticides or selected metabolites from different families (herbicides, insecticides, fungicides) in surface water samples. The optimization of parameters that could influence SBSE-LD efficiency was carried out by means of experimental design. Optimized conditions were established as follows concerning extraction time, stirring speed, aqueous medium characteristics (ionic strength and polarity) and back desorption solvent and time, respectively: 3 h (800 rpm), addition of 10% of sodium chloride, no addition of methanol as organic modifier, and 15 min ultrasonic desorption in equivolume mixtures of acetonitrile-methanol. A specific and thorough cleanup procedure was developed and applied to each stir bar to avoid possible carry-over between consecutive extractions with the same stir bar. Pesticide quantification in water was achieved thanks to matrix matched calibration. Mean recoveries ranged from 93 to 101% (RSD <17%, n=30). Validated limits of quantification in matrix were between 0.02 and 1 µg L−1, depending on the compound. A specific experimental design was conducted to evaluate the measurement uncertainty, which was comprised between 13 and 51%, whatever the pesticide and the concentration level. The applicability of the SBSE-LD-LCMSMS method was evaluated by analyzing surface water samples and by comparing with conventional solid phase extraction-LC-MSMS procedure.
An easy to perform analytical method for the determination of three bisphenol compounds (BPs) in commonly used personal care products (PCPs) is presented. Ethylene glycol-silicone (EG-Silicone) coated stir bars, which have recently become commercially available, are evaluated in this study for the simultaneous determination of bisphenol A (BPA), bisphenol F (BPF) and bisphenol Z (BPZ) by stir bar sorptive extraction (SBSE) in combination with thermal desorption-gas chromatography-mass spectrometry (TD-GC-MS). This new sorptive extraction phase allows the analysis of these compounds without any previous derivatization procedure. Different parameters affecting both SBSE extraction and thermal desorption were carefully optimized, using experimental designs based on the Taguchi orthogonal arrays. The procedure was applied to analyzing easily bought PCPs, providing detection limits of about 8ngg(-1), with precisions lower than 11% in terms of relative standard deviation. Recovery studies performed at two different concentration levels provided satisfactory values for all the compounds. The analyzed personal care samples contained BPA at concentration levels ranging from 30.9 to 88.3ngg(-1).
A new concept of "dual-phase dual stir bar sorptive extraction (SBSE)" was proposed to simultaneously extract six preservatives with different polarities (logKo/w values of 1.27-3.41), namely, benzoic acid (BA), sorbic acid (SA), methyl p-hydroxybenzoate (MP), ethyl p-hydroxybenzoate (EP), propyl p-hydroxybenzoate (PP), and butyl p-hydroxybenzoate (BP). The dual-phase dual SBSE apparatus was consisted of two differently coated stir bars, a 3-aminopropyltriethoxysilane (APTES)-hydroxy-terminated silicone oil (OH-TSO)-coated stir bar that was prepared by sol-gel technique and a C(18) silica (C(18))-polydimethylsiloxane (PDMS)-coated stir bar that was prepared by adhesion. In dual-phase dual SBSE, the two stir bars with different coatings were placed in the same sample solution for the simultaneous extraction of the target analytes with different polarities, and then the bars were desorbed in the same desorption solvent. The extraction performance of the dual-phase dual SBSE for the six preservatives was evaluated by comparing with the conventional SBSE (individual stir bar) with different coatings, including commercial PDMS, homemade PDMS, C(18)-APTES-OH-TSO, APTES-OH-TSO, and C(18)-PDMS. The experimental results showed that the dual-phase dual SBSE had the highest extraction efficiency for the six target preservatives. Based on this fact, a novel method by combining the dual-phase dual SBSE which was consisted of the APTES-OH-TSO-coated and C(18)-PDMS-coated stir bars with high-performance liquid chromatography-ultraviolet detection (HPLC-UV) was developed for the simultaneous analysis of six target beverage preservatives in beverages. Under optimal conditions, the limits of detection (LODs) for six target preservatives ranged from 0.6 to 2.7μgL(-1) with the relative standard deviations (RSDs) of 4.6-9.2% (C(BA,SA)=5μgL(-1),C(MP)=20μgL(-1),C(EP,PP,BP)=10μgL(-1), n=7). The enrichment factors (EFs) were approximately 16-42-fold (theoretical EF was 50-fold). The proposed method was validated by the analysis of six target preservatives in three kinds of beverage samples, and the recoveries for the spiked samples were in the range of 76.6-118.6% for cola, 74.6-17.5% for orange juice, and 83.0-119.1% for herbal tea, respectively.
In this work, a new method of polydimethylsiloxane/polythiophene (PDMS/PTH) coated stir bar sorptive extraction (SBSE) coupled to liquid desorption-large volume injection-gas chromatography-flame photometric detection (LD-LVI-GC-FPD) was proposed for the determination of organophosphorus pesticides (OPPs, including phorate, fenitrothion, malathion, parathion and quinalphos) in environmental water samples. Polythiophene was synthesized by chemical oxidative polymerization method, and the PDMS/PTH coated stir bar was prepared by sol-gel technique. The preparation reproducibility of PDMS/PTH coated stir bar was good with the relative standard deviations (RSDs) ranging from 3.9% to 8.1% (n=7) in one batch, and from 5.9% to 14.9% (n=6) among different batches. To get the best extraction performance for OPPs, the operation parameters affecting the extraction efficiency of SBSE, including extraction time, desorption time, stirring rate and ionic strength, were investigated. Under the optimal conditions, the limits of detection (S/N=3) were found to be in the range of 0.011-0.038μg/L for the five target OPPs, and the linear range was from 0.2 to 100μg/L for phorate and 0.1-100μg/L for other four OPPs. The RSDs of the proposed method were in the range of 4.0-9.8% (n=8, c=1μg/L) and the enrichment factors were varied from 56.7 to 80.9-fold (theory enrichment factor was 100-fold). The proposed method was applied to the analysis of OPPs in East Lake water and ground water samples with recovery in the range of 77.7-119.8% and 79.1-109.8% for the spiked East Lake water and ground water samples, respectively.
Identification and determination of leachable components are essential for the safety assessment of implantable medical devices. The safety concern threshold (SCT) for leachable components is 0.15μg/day for genotoxic or carcinogenic compounds and 1.5μg/day for others. Regulatory agencies require extraction of a whole medical device using an extraction media that simulates in vitro conditions. Large-sized medical devices therefore require large volumes of aqueous media, leading to extracts of very low concentrations of the targeted analytes. Analysis of these dilute solutions is often challenging, and pre-concentration steps are time consuming and can cause significant sample loss. Stir bar sorptive extraction (SBSE) has proven to be a very useful sample preparation technique that is simple and uses no (or minimal (<1ml)) aqueous or organic solvents. When combined with a highly selective and sensitive GC-MS/MS analysis, volatile and semi-volatile leachable components can be determined at levels below the SCT of 150ng/device. An SBSE-GC-MS/MS method using multiple reaction monitoring detection was validated for determination of antioxidant related leachable breakdown products from orthopedic knee-inserts made from ultra high molecular weight polyethylene.
A new coating material was used for a stir bar sorptive extraction (SBSE) method coupled to a high throughput sample analysis technique. This allowed for a simple procedure for fast determinations of eight steroid hormones (estriol, estradiol, ethynylestradiol, estrone, progesterone, medroxyprogesterone, levonorgestrel, northindrone) in water. Sample pre-treatment was performed using an in-house SBSE method based on a polydimethylsiloxane/phenyltrimethylsiloxane/β-cyclodextrin sol-gel material. The analytes were desorbed by liquid extraction prior to their analysis by laser diode thermal desorption/atmospheric pressure chemical ionization coupled to tandem mass spectrometry (LDTD-APCI-MS/MS). Several parameters, including ionic strength, volume and time of extraction as well as volume and time of desorption, were investigated to maximize extraction efficiency by SBSE in aqueous solutions. The in-house stir bar showed good reproducibility and could be used for at least 50 extractions without affecting analytical performance. The recoveries of the spiked steroid hormones ranged from 55% to 96% in all water matrices studied (HPLC grade water, tap water and raw wastewater). Only one compound showed poor recovery values (<2% for estriol) in all matrices. The method detection limits (MDLs) in real matrices were within the range of 0.1-0.3μgL(-1) except for estriol at 48μgL(-1). The extraction performance of the in-house SBSE for the eight selected hormones was also compared with that of a commercially-available stir bar coated with polydimethylsiloxane (PDMS). This novel stir bar coating could prove to be useful method for the detection and quantification of trace levels of steroid hormones.
The main objective of this work is to develop an accurate, sensitive, simple and cost-effective method for the determination of tributyltin species (as cationic form) in seawater at ultra-trace levels. The method is based on the use of stir bar sorptive extraction (SBSE) followed by solvent desorption and liquid chromatography tandem mass spectrometry (SD-LC-MS/MS (QqQ)) analysis, operating in positive electrospray ionisation (ESI) and in the selected reaction monitoring (SRM) mode. Extraction and LC-MS/MS parameters were accurately optimised to achieve the highest recoveries and to enhance the analytical characteristics of the method. The different parameters that affect the extraction procedure, the chromatographic and spectrometric conditions, and the surrogate selection were evaluated. In contrast with previously proposed methods, the proposed method involves a simplified sample treatment. Quality parameters such as linearity, accuracy in terms of trueness and precision, uncertainty and specificity were examined with good results. The evaluation of two surrogates (tri-n-propyltin chloride and tripentyltin chloride) was also carried out. The limit of detection (LOD) and limit of quantification (LOQ) obtained were 0.8 and 2.5ngL(-1), respectively. Precision, expressed as relative standard deviation (%RSD), was lower than 16%, and the determination coefficient (R(2)) was higher than 0.990 with a residual deviation for each calibration point lower than ±25%. Mean recoveries were between 92% and 102%. The accuracy of the method was also studied by participating in an external proficiency testing scheme. After validation, the method was applied to the analysis of all tributyltin species found in natural seawater samples. The method meets the requirements of the United States Environmental Protection Agency (US-EPA).
In this study, novel off/on-site stir bar sorptive extraction (SBSE) approaches with a home-made portable electric stirrer have been developed for the analysis of polycyclic aromatic hydrocarbon compounds (PAHs). In these approaches, a miniature battery-operated electric stirrer was employed to provide agitation of sample solutions instead of the commonly used large size magnetic stirrer powered by alternating current in conventional SBSE process, which could extend the SBSE technique from the conventional off-site analysis to the on-site sampling. The applicability of the designed off/on-site SBSE sampling approaches was evaluated by polydimethylsiloxane (PDMS) coating SBSE-high performance liquid chromatography-fluorescence detection (HPLC-FLD) analysis of six target PAHs in environmental water. The home-made portable electric stirrer is simple, easy-to-operate, user friendly, low cost, easy-to-be-commercialized, and can be processed in direct immersion SBSE, headspace sorptive extraction (HSSE) and continuous flow (CF)-SBSE modes. Since the stir bar was fixed onto the portable device by magnetic force, it is very convenient to install, remove and replace the stir bar, and the coating friction loss which occurred frequently in conventional SBSE process could be avoided. The parameters affecting the extraction of six target PAHs by the home-made portable SBSE sampling device with different sampling modes were studied. Under the optimum extraction conditions, good linearity was obtained by all of three SBSE extraction modes with correlation coefficient (R) higher than 0.9971. The limits of detection (LODs, S/N=3) were 0.05-3.41ngL(-1) for direct immersion SBSE, 0.03-2.23ngL(-1) for HSSE and 0.09-3.75ngL(-1) for CF-SBSE, respectively. The proposed portable PDMS-SBSE-HPLC-FLD method was applied for the analysis of six target PAHs in East Lake water, and the analytical results obtained by on-site SBSE sampling were in good agreement with that obtained by off-site SBSE sampling. The accuracy of the developed method was evaluated by recovery test and the recoveries for the spiked sample were found to be in the range of 87.1-122.8% for off-site CF-SBSE, 88.8-114.3% for on-site sampling, and 87.7-123.6% for off-site SBSE, respectively. The developed method is one of the most sensitive methods for PAHs determination and the home-designed SBSE system is feasible for the field sampling.
In this work, partially sulfonated polystyrene-titania (PSP-TiO(2)) organic-inorganic hybrid stir bar coating was prepared by sol-gel and blending methods, and a new method of PSP-TiO(2) coating stir bar sorptive extraction (SBSE)-high performance liquid chromatography (HPLC)-inductively coupled plasma mass spectrometry (ICP-MS) was established for the analysis of seleno-amino acids (selenocystine (SeCys(2)), methylseleno-cysteine (MeSeCys), selenomethionine (SeMet) and selenoethionine (SeEt)) and seleno-oligopeptides (γ-glutamyl-Se-methyl-selenocysteine (γ-GluMeSeCys) and selenodiglutathione (GS-Se-SG)) in biological samples. The prepared high polar PSP-TiO(2) hybrid coating avoided the swelling of PSP and cracking of TiO(2) coating by combining the good film-forming property of PSP with the high mechanical strength of TiO(2). The scanning electron microscope (SEM) showed that no obvious swelling and damage occurred for the PSP-TiO(2) hybrid stir bar coating after 30 extraction/desorption cycles. The preparation reproducibility of PSP-TiO(2) coated stir bar, evaluated with the relative standard deviations (RSDs), was in the range of 6.7-12.6% (n=5) in one batch, and 9.9-17.6% (n=7) among different batches. The limits of detection (LODs) of the developed method for six target selenium species were in the range of 50.2-185.5 ngL(-1) (as (77)Se) and 45.9-158.8 ngL(-1) (as (82)Se) with the RSDs within 4.9-11.7%. The dynamic linear range was found to cover three orders of magnitude with correlation coefficient of 0.9995-0.9999. The developed method was applied for the analysis of Certified Reference Material SELM-1 selenium enriched yeast and the determined values were in good agreement with the certified values. The method has also been applied for the analysis of seleno-amino acids and seleno-oligopeptides in human urine and garlic samples. Different from the conventional organic polymer SBSE coatings (such as polydimethylsiloxane, PDMS), the extraction mechanism of PSP-TiO(2) organic-inorganic hybrid SBSE coating was based on the cation exchange interaction, which made it feasible to directly extract high polar seleno-amino acids and seleno-oligopeptides in biological samples without derivatization. This coating could also be suitable for stir bar sorptive extraction of other cationic compounds from the environmental and biological samples.
A method for the determination of seven perfluorinated carboxylic acids and perfluorooctane sulphonate (PFOS) in aqueous samples using low-cost polymeric sorptive extraction as sample preparation technique, followed by liquid chromatography-tandem mass spectrometry (LC-MS/MS) determination has been developed and validated. Simplicity of the analytical procedure, low volume of solvent and sample required, low global price and a good selectivity providing cleaner extracts are the main advantages of this extraction technique. Polydimethylsiloxane (PDMS) and polyethersulfone (PES) materials were evaluated and compared to achieve the best extraction efficiencies. Hence, different variables have been optimized, viz.: sample pH, concentration of an ion-pairing agent (tetrabutylammonium), ionic strength, sample volume, extraction time, desorption solvent volume, desorption time and the need for auxiliary desorption techniques (sonication). Overall, PES leaded to a better sensitivity than PDMS, particularly for the most polar compounds, reaching detection limits (LODs) in the 0.2-20 ng L(-1) range. The precision of the method, expressed as relative standard deviation (RSD), was lower than 16%. Finally, the PES material was employed for the analysis of sea, sewage and fresh water samples. Perfluoroheptanoic acid (PFHpA), perfluorooctanoic acid (PFOA), perfluorononanoic acid (PFNA) and perfluorodecanoic acid (PFDA) were detected in all the analyzed influent samples reaching levels of up to 401 ng L(-1). In surface water, perfluorohexanoic acid (PFHxA) exhibited the highest concentrations, up to 137 ng L(-1).
In Stir Bar Sorptive Extraction (SBSE) organic analytes are enriched from aqueous samples by sorption onto a thick film of polydimethylsiloxane (PDMS) coated on a glass-enveloped magnet. Sampled analytes are recovered by thermodesorption (TDS) and analysed on-line by cGC-MS. This study evaluates the SBSE recovery as a function of KO/W, the phase ratio (β), PDMS volume (20, 40, and 110 μL), sample volumes (4, 10, 100, and 1000 mL), and sampling time (0.67, 1, 2, 4, 5, 6, and 24 h) for three pesticides with different KO/W [parathion methyl (KO/W: 7.24×102), β-endosulfan (KO/W: 6.8×103), and buprofezin (KO/W: 2.0×104)]. Experimental recoveries with SBSE in reasonable sampling times were found to be mainly conditioned by β, which must be as low as possible either by operating on small sample volumes or by using stir bars coated with high PDMS volume when samples of relatively large volume are analysed.
The theory and practice of a novel approach for sample enrichment, namely the application of stir bars coated with the sorbent polydimethylsiloxane (PDMS) and referred to as stir bar sorptive extraction (SBSE) are presented. Stir bars with a length of 10 and 40 mm coated with 55 and 219 μL of PDMS liquid phase, respectively were applied. The 10-mm stir bars are best suited for stirring sample volumes from 10 up to 50 mL whereas 40-mm stir bars are more ideal for sample volumes up to 250 mL. Depending on sample volume and the stirring speed, typical stirring times for equilibration are between 30 and 60 min. The performance of SBSE is illustrated with the analysis of volatile and semivolatile micropollutants from aqueous samples. Detection limits using mass selective detection are in the low ng/L range for a wide selection of analytes from the EPA priority pollutant lists including analytes ranging in volatility from 1,1,1-trichloroethane to chrysene. For the extraction of selected compounds from 200-mL samples, detection limits below 0.1 ng/L are reached in the selected ion monitoring mode. A comparison between SBSE and solid-phase microextraction is made. ©1999 John Wiley & Sons, Inc. J Micro Sep 11: 737–747, 1999
This paper describes a method for the simultaneous determination of bisphenol A (BPA), bisphenol F (BPF), bisphenol Z (BPZ) and biphenol (BP), using stir bar sorptive extraction (SBSE) in combination with thermal desorption-gas chromatography-mass spectrometry (TD-GC-MS). Several parameters affecting both extraction and thermal desorption of the SBSE stages were carefully optimized by multivariate designs. SBSE was performed with two derivatization procedures, in situ acetylation and in tube silylation, and the results were compared with those obtained when the analytes were not derivatized. The proposed method, determining the analytes as acyl derivatives, was applied to analyze commercially canned beverages, as well as the filling liquids of canned vegetables, providing detection limits of between 4.7 and 12.5 ng L⁻¹, depending on the compound. The intraday and interday precisions were lower than 6% in terms of relative standard deviation. Recovery studies at two concentration levels, 0.1 and 1 μg L⁻¹, were performed providing recoveries in the 86-122% range. The samples analyzed contained higher concentrations of BPA than of the other analytes.
In this study, a sensitive, selective and reliable analytical method by combining zirconia (ZrO₂) coated stir bar sorptive extraction (SBSE) with large volume sample stacking capillary electrophoresis-indirect ultraviolet (LVSS-CE/indirect UV) was developed for the direct analysis of chemical warfare agent degradation products of alkyl alkylphosphonic acids (AAPAs) (including ethyl methylphosphonic acid (EMPA) and pinacolyl methylphosphonate (PMPA)) and methylphosphonic acid (MPA) in environmental waters. ZrO₂ coated stir bar was prepared by adhering nanometer-sized ZrO₂ particles onto the surface of stir bar with commercial PDMS sol as adhesion agent. Due to the high affinity of ZrO₂ to the electronegative phosphonate group, ZrO₂ coated stir bars could selectively extract the strongly polar AAPAs and MPA. After systematically optimizing the extraction conditions of ZrO₂-SBSE, the analytical performance of ZrO₂-SBSE-CE/indirect UV and ZrO₂-SBSE-LVSS-CE/indirect UV was assessed. The limits of detection (LODs, at a signal-to-noise ratio of 3) obtained by ZrO₂-SBSE-CE/indirect UV were 13.4-15.9 μg/L for PMPA, EMPA and MPA. The relative standard deviations (RSDs, n=7, c=200 μg/L) of the corrected peak area for the target analytes were in the range of 6.4-8.8%. Enhancement factors (EFs) in terms of LODs were found to be from 112- to 145-fold. By combining ZrO₂ coating SBSE with LVSS as a dual preconcentration strategy, the EFs were magnified up to 1583-fold, and the LODs of ZrO₂-SBSE-LVSS-CE/indirect UV were 1.4, 1.2 and 3.1 μg/L for PMPA, EMPA, and MPA, respectively. The RSDs (n=7, c=20 μg/L) were found to be in the range of 9.0-11.8%. The developed ZrO₂-SBSE-LVSS-CE/indirect UV method has been successfully applied to the analysis of PMPA, EMPA, and MPA in different environmental water samples, and the recoveries for the spiked water samples were found to be in the range of 93.8-105.3%.
This article presents a method employing stir bar coated with a film of poly (methyl methacrylate/ethyleneglycol dimethacrylate) (PA-EG) and polydimethylsiloxane (PDMS) in combination with liquid desorption (LD) using ionic liquid, followed by high performance liquid chromatography (HPLC) equipped with ultraviolet (UV) detection for the determination of carvedilol in human serum samples. Stir bar sorptive extraction (SBSE) variables, such as desorption and extraction time and temperature, desorption solvent and pH of the matrix were optimized, in order to achieve suitable analytical sensitivity in a short period of time. Also, the concentration effect of 1-methyl-3-octylimidazolium tetrafluoroborate [Omim][BF4] ionic liquid on the efficiency of LD was investigated. A comparison between PA-EG/SBSE and PDMS/SBSE was made by calculating the experimental recovery and partition coefficient (K), where PA-EG phase demonstrated to be an excellent alternative for the enrichment of the carvedilol from serum samples. The effect of [Omim][BF4] on carryover was studied and no carryover was observed. Under optimized experimental conditions, the analytical performance showed excellent linear dynamic range, with correlation coefficients higher than 0.999 and limits of detection and quantification of 0.3 and 1.0 ng mL(-1), respectively. Intra- and inter-day recovery ranged from 94 to 103% and the coefficients of variations were less than 3.2%. The proposed method was shown to be simple, highly sensitive and suitable for the measurement of trace concentration levels of carvedilol in biological fluid media.
The aim of this article is to present an analytical application of stir bar sorptive extraction (SBSE) coupled to HPLC-fluorescence detection (FLD) for the quantification of fluoxetine (FLX), citalopram (CIT) and venlafaxine (VLF) and their active metabolites – norfluoxetine (NFLX), desmethyl- (DCIT) and didesmethylcitalopram (DDCIT) and o-desmethylvenlafaxine (ODV) – in plasma, urine and brain tissue samples. All the parameters influencing adsorption (pH, ion strength, organic modifier addition, volume, extraction time and temperature) and desorption (desorption solvent composition, time, temperature and desorption mode) of the analytes on the stir bar have been optimized. For each matrix, the analytical method has been assessed by studying the linearity and the intra- and interday accuracy (89–113%) and precision (RSD < 13%). The improvement of the quantification limits (0.2–2 μg l−1 for plasma, 2–20 ng g−1 for brain tissue and 1–10 μg l−1 for urine, depending on the respective response for analytes) and the development of a procedure for all the matrices make this method useful in clinical and forensic analysis.
Solid-phase microextraction (SPME) is a recent technique for sample preparation. It has been used successfully to analyze environmental pollutants in a variety of matrices such as soils, water, and air. SPME is a solvent-free technique which has a number of advantages over more conventional sample preparation techniques such as liquid–liquid extraction (LLE) and solid-phase extraction (SPE). We describe the most recent developments in SPME and some which are being developed, including its coupling to HPLC and CE, the use of new fibers, and the automation of the entire SPME process and its application to field analysis. A summary is given of the most important parameters for applying this extraction technique to the analysis of environmental samples.
Among the aroma compounds present within grapes, a significant part is assumed to come from specific odourless precursors found mainly as glycosidic compounds which are known as bound fraction. In this paper, the individual composition of non-aromatic red grape bound fraction has been assayed for first time by SBSE–GC–MS and compared with the global total aroma potential measured spectrophotometrically at the wineries, in which the anthocyanins interferences have been removed. Glycosidic aroma compounds have been extracted by macerating grapes with different extractants (EtOHaq or SO2) at different times and subjected to acidic hydrolysis at 70 °C for 2 h. The best extraction condition, expressed as the higher aroma compounds concentration (terpenes + C13 norisoprenoids + 2-phenylethanol + C6 compounds), was the ethanolic aqueous extraction carried out for 2 h, reducing considerably the extraction times proposed in the literature. The method was successfully used to discriminate non-aromatic red grape varieties, (Petit-Verdot, Merlot and Monastrell) being limonene, linalool, 2-hexen-1-ol, TDN and 2-phenylethanol the aromas that contributed most to the differentiation. An aromatic white table grape such as Early sugar was also assayed to check its higher volatile composition in comparison with the other red varieties. The percentage of favourable aromas (terpenes + C13 norisoprensoids + bencene derivates) is always higher than the unfavourable ones (C6) for all tested varieties, especially Early Sugar. It has also been observe that the spectrophotometric measurements are overestimated when compared with SBSE–GC–MS, probably due to the free sugar content and other glycosidic compounds.
Cd(II) imprinted 3-mercaptopropyltrimethoxysilane (MPTS)-silica coated stir bar was prepared by sol-gel technique combining with a double-imprinting concept for the first time and was employed for stir bar sorptive extraction (SBSE) of trace Cd(II) from water samples followed by inductively coupled plasma mass spectrometry (ICP-MS) detection. A tetramethoxysilane (TMOS) coating was first in situ created on the glass bar surface. Afterward, a sol solution containing MPTS as the functional precursor, ethanol as the solvent and both Cd(II) and surfactant micelles (cetyltrimethylammonium bromide, CTAB) as the template was again coated on the TMOS bar. The structures of the stir bar coating were characterized by FT-IR spectroscopy. Round-bottom vial was used for the extraction of Cd(II) by SBSE to avoid abrasion of stir bar coatings. The factors affecting the extraction of Cd(II) by SBSE such as pH, stirring rate and time, sample/elution volume and interfering ions have been investigated in detail, and the optimized experimental parameters were obtained. Under the optimized conditions, the adsorption capacities of non-imprinted and imprinted coating stir bars were found to be 0.5 μg and 0.8 μg bar(-1). The detection limit (3σ) based on three times standard deviations of the method blanks by 7 replicates was 4.40 ng L(-1) and the relative standard deviation (RSD) was 3.38% (c=1 μg L(-1), n=7). The proposed method was successfully applied for the analysis of trace Cd(II) in rain water, East Lake and Yangtze River water. To validate the proposed method, certified reference material of GSBZ 50009-88 environmental water was analyzed and the determined value is in a good agreement with the certified value. The developed method is rapid, selective, sensitive and applicable for the analysis of trace Cd(II) in environmental water samples.
A simple, rapid, sensitive, inexpensive and less sample consuming method of C(18)-stir bar sorptive extraction (SBSE)-high performance liquid chromatography (HPLC)-tandem mass spectrometry (MS/MS) was proposed for the determination of six sulfonamides in milk and milk powder samples. C(18) silica particles coated stir bar was prepared by adhesion method, and two kinds of adhesive glue, polydimethylsiloxane (PDMS) sol and epoxy glue were tried. It was found that the C(18)-coated stir bar prepared by PDMS sol as adhesive glue is more robust than that prepared by epoxy glue when liquid desorption was employed, in terms of both lifetime and organic solvent tolerance. The preparation of C(18) stir bar was simple with good mechanic strength and the stir bar could be reused for more than 20 times. Granular coating has relatively high specific surface area and is propitious to sorptive extraction based process. Compared to conventional PDMS SBSE coating, C(18) coating shows good affinity to the target polar/weak polar sulfonamides. To achieve optimum SBSE extraction performance, several parameters including extraction and desorption time, ionic strength, sample pH and stirring speed were investigated. The detection limits of the proposed method for six sulfonamides were in the range of 0.9-10.5 μg/L for milk and 2.7-31.5 μg/kg for milk powder. Good linearities were obtained for sulfonamides with the correlation coefficients (R) above 0.9922. Finally, the proposed method was successfully applied to the determination of sulfonamides in milk and milk powder samples and satisfied recoveries of spiked target compounds in real samples were obtained.
A monolithic, hydrophilic stir bar coating based upon a copolymer of methacrylic acid and divinylbenzene [poly(MAA-co-DVB)] was synthesised and evaluated as a new polymeric phase for the stir bar sorptive extraction (SBSE) of polar compounds from complex environmental water samples. The experimental conditions for the extraction and liquid desorption in SBSE were optimised. Liquid chromatography-triple quadrupole mass spectrometry (LC-MS/MS) was used for the determination of a group of polar pharmaceuticals in environmental water matrices. The extraction performance of the poly(MAA-co-DVB) stir bar was compared to the extraction performance of a commercially available polydimethylsiloxane stir bar; it was found that the former gave rise to significantly higher extraction efficiency of polar analytes (% recovery values near to 100% for most of the studied analytes) than the commercial product. The developed method was applied to determine the studied analytes at low ng L⁻¹ in different complex environmental water samples.
