Article

Development of a novel electrochemical sensor based on electropolymerized molecularly imprinted polymer for selective detection of sodium lauryl sulfate in environmental waters and cosmetic products

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... Several works report on the use of aminothiophenol (ATP) as monomer for preparing MIP layers. For example, Motia et al. [38] electropolymerized 2-ATP on gold SPE in the presence of sodium lauryl sulphate as template. 2-ATP was also immobilized on the electrode surface via thiol-Au bonding to form a more stable film prior to electropolymerization. ...
... 2-ATP was also immobilized on the electrode surface via thiol-Au bonding to form a more stable film prior to electropolymerization. The MIP sensor was able to selectively detect sodium lauryl sulphate with a LOD of 0.18 pM and was applied for the analysis of environmental samples and cosmetic products [38]. Guo et al. [9] developed a generic protocol that can be applied also to nonelectroactive targets based on 4-ATP as monomer. ...
... Electropolymerization is simpler and faster, can perform in-situ on the surface of the electrode and it proposes a better command of the film thickness by regulating the scan rates and the number of cycles during the process. Moreover, the whole polymerization steps layer-by-layer can be monitored on the digital screen [85][86][87]. For instance, a study was performed in which the number of cycles was scanned from 2 to 8 and it was found that the electrode's sensitivity was attained maximum with 5 cycles, and after the 5 cycles, it decreased. ...
Article
Antibiotics are used extensively to avert or cure bacterial infections in humans, plants, and animals. The prevalent disbursement and superfluous usage of antibiotics led to environmental and health concerns globally. The scientific community shifts research from conventional to new and advanced analytical techniques that can detect antibiotics at very low concentrations. Timely and organized assessment of the emerging scientific advancements in the field of biosensing is vital to develop new advanced techniques for the detection of antibiotics. In this context, molecularly imprinted polymers (MIPs) can imitate enzymes, antibodies, and other biorecognition elements with high specificity, rich affinity, and robustness. Moreover, cheap, and simple synthesis strategies, along with reproducibility and stability emphasize the benefits of MIPS. Although MIPs have numerous advantages such as selective binding sites, high stability, and specificity, there are some bottlenecks like low conductivity and low electro-catalytic activity. To enhance their analytical performance and overcome these limitations, MIPs have been integrated with functional carbon nanomaterials (CNMs). The CNMs provide highly conductive, specific, and selective substrates for electrochemical antibiotic sensing. The CNMs decorated MIPs based electrochemical sensors possess numerous advantages including user-friendly, portability, point-of-care (POC) detection with highly sensitive, selective, and rapid outcomes. This review systematically explores the emergence of MIPs and CNMs based MIPs for electrochemical sensing of antibiotics along with the related challenges and future perspectives carefully and critically. The outcomes of this report pave the way for developing portable, cost-effective, easy to use and POC devices for the detection of antibiotics for environmental monitoring.
... Ortho-amino thiophenol (O-ATP) has been used to prepare MIP-based domains [57]. This monomer is able to interact via electropolymerization with target molecules through hydrogen bonding [58]. In this study, Iron oxide-Graphene, gold nanoparticles, and CNT (AuFe 2 O 3 -GrCNT) have been used to prepare nanocomposites for amplifying the signal on the surface of the carbon-glass electrode (GCE). ...
Article
A new Molecularly Imprinted Polymer (MIP)-based electrochemical sensor was used to detect neonatal jaundice in saliva and serum samples. The Bilirubin (BR) detection sensor is fabricated by 2-aminothiophenol (2-ATP) polymerization on MIP/AuFe2O3-GrCNT/GCE using a Glassy Carbon Electrode (GCE). BR is an important factor in the body. Excessive amounts of BR can cause severe and irreversible damage to the brain and nerves, especially in infants. Engraving detection sites created by washing patterns from engraved polymer make it possible to detect the target analyte by creating three-dimensional holes. The electrochemical behavior of the sensor was evaluated by Differential Pulse Voltammetry (DPV), Cyclic Voltammetry (CV), and Electrochemical Impedance Spectroscopy (EIS) techniques in 10.0 mM of [Fe(CN)6]-3/-4 solution with 0.1 M of KCl. Surface analysis was performed by Scanning Electron Microscopy (SEM) and the accuracy of the research measurement was checked by High Pressure Liquid Chromatography (HPLC), After creating optimal conditions in two domains, two wide linear responses from (3.7 to 13.2 nM) and (3.7 to 13.0 pM) were obtained. Limit of Detection (LOD) values were calculated to be 1.54 nM and 1.36 pM, and Limit of Quantitation (LOQ) values were calculated to be 5.14 nM and 5.3 pM. Owing to rapid detection ability, cost-effectiveness, low sample consumption, high sensitivity, extremely low interference, and good stability, this sensor can be a promising tool to detect the cause of neonatal jaundice in the saliva and serum of the infants.
... Prior to electropolymerization, the surface of the electrode was modified with a layer of 2-ATP by dripping the solution on the electrode surface. The electrochemical response, by CV, DPV and EIS, indicated that the sensor presented good affinity for the SLS, with a limit of detection of 0.18 pg/mL [80]. ...
Article
Full-text available
Molecular imprinting (MI) is the most available and known method to produce artificial recognition sites, similar to antibodies, inside or at the surface of a polymeric material. For this reason, scholars all over the world have found MI appealing, thus developing, in this past period, various types of molecularly imprinted polymers (MIPs) that can be applied to a wide range of applications, including catalysis, separation sciences and monitoring/diagnostic devices for chemicals, biochemicals and pharmaceuticals. For instance, the advantages brought by the use of MIPs in the sensing and analytics field refer to higher selectivity, sensitivity and low detection limits, but also to higher chemical and thermal stability as well as reusability. In light of recent literature findings, this review presents both modern and dedicated methods applied to produce MIP layers that can be integrated with existent detection systems. In this respect, the following MI methods to produce sensing layers are presented and discussed: surface polymerization, electropolymerization, sol–gel derived techniques, phase inversionand deposition of electroactive pastes/inks that include MIP particles.
... A novel molecularly imprinted polymer (MIP) sensor was developed by Motia et al. (2018) for the electrochemical detection of sodium lauryl sulfate (SLS). ...
Book
The worldwide trend toward urbanization leads to increasing contamination of aquatic environments by thousands of synthetic and natural compounds which are known as micropollutants. Although most of these chemicals occur at low concentrations, due to persistent, bioaccumulative, and toxic features, many of them show the considerable toxicological concerns and health side effects. Because of their partial removal during conventional wastewater treatment processes and lack of international safety and environmental standards, a large number of micropollutants and their metabolites still remained there and released in the nearby aquatic environments. In recent years, there has been a growing tendency to research about micropollutants’ impacts on the receiving environment and human health. These compounds are more significantly sensitive in detecting processes than classic compounds. Therefore, using micropollutants as environmental indicators for anthropogenic activities is a common method and frequently applied today. This book on micropollutants and challenges emerging in the aquatic environments and treatment processes contains comprehensive information on the fate and removal methods of the various emerging micropollutants from water and wastewater plants and their human health threats. This book addresses the needs of both researchers and graduate students in fields of environmental health engineering, environmental engineering, civil engineering, chemistry, etc.
... It introduces a novel development and research to analytical chemistry. [7][8][9][10] Owing to high speci-city for target molecules, remarkable sensitivity, and simple operation, 11 MIECS have extensive applications in the elds of food security, pesticide residues, environmental detection, clinical medicine and so on. [12][13][14] To increase the surface area of the modied electrode, materials with excellent performance are usually incorporated. ...
Article
Full-text available
In this paper, a composite composed of carboxylated multi-wall carbon nanotubes (cMWCNT) incorporated in a metal-organic framework (MOF-199) has been synthesized using 1,3,5-benzoic acid as a ligand through a simple solvothermal method. The synthesized cMWCNT/MOF-199 composite was characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR) and X-ray diffractometry (XRD). The cMWCNT/MOF-199 hybrids were modified on the surface of glassy carbon electrodes (GCE) to prepare a molecularly imprinted electrochemical sensor (MIECS) for specific recognition of 3-chloro-1,2-propanediol (3-MCPD). The electrodes were characterized by differential pulse voltammetry (DPV), electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV). Under optimal conditions, the electrochemical sensor exhibited an excellent sensitivity and high selectivity with a good linear response range from 1.0 × 10-9 to 1.0 × 10-5 mol L-1 and an estimated detection limit of 4.3 × 10-10 mol L-1. Furthermore, this method has been successfully applied to the detection of 3-MCPD in soy sauce, and the recovery ranged from 96% to 108%, with RSD lower than 5.5% (n = 3), showing great potential for the selective analysis of 3-MCPD in foodstuffs. This journal is
... When it comes to the electrochemistry that has boomed in potent detection of molecules, all the hindrance above are settled, thanks to the staid properties of simplicity, sensitivity, stability, affordability, easy process as well as the requirement of modest equipment [12]. However, the selectivity of target analyte detection is also in high demand due to the variety of possible sample matrices, complexity, and mutual interference of the similar chemical properties. ...
Article
Butylated hydroxyanisole (BHA), one of the most widely used synthetic antioxidants in food, has instigated grave alarm due to its potential poisonous upshot on human health. Accordingly, its monitoring act as a pivotal role in the food consumption. Regarding this issue, the present research work highlights a facile synthesis approach for the development of a novel electrochemical sensor to quantitatively determine BHA, based on functionalized screen-printed carbon electrode (SPCE) with molecularly imprinted polymer (MIP) and gold nanoparticles (AuNPs). The polymer matrix composed of chitosan (CS) was combined with AuNPs to complete the fabrication of the electropolymerized MIP sensor in the presence of BHA as templates. Electrochemical impedance spectroscopy (EIS), differential pulse voltammetry (DPV) and cyclic voltammetry (CV) were used for the help of the electrochemical characterizations. Similarly, the electrodes surfaces morphologies of the different elaboration steps were characterized by scanning electron microscopy (SEM), Fourier transform infrared (FT-IR) spectroscopy and atomic force microscopy (AFM). The achieved returns attested satisfactory sensitivity and selectivity to BHA compared to interfering substances including ascorbic acid and citric acid. In optimal experimental conditions, the MIP sensor specifies a concentration range of 0.01-20 μg/mL, with a low detection limit of 0.001 μg/mL (signal-to-noise ratio S/N = 3). In addition, the reproducibility, the stability and the repeatability of the MIP sensor were validated. Consequently, the responses dedicated from the MIP sensor agreed with those achieved from the spectrophotometry as validation method for BHA determination in food samples using partial least squares (PLS) prediction technique. According to the achieved outcomes, the MIP sensor could be good vista for food control.
... For that, a variety of nanomaterials with good conductivity and large surface area have been introduced to modify electrodes, such as carbon materials [22] and metal nanoparticles [23]. The carbon representatives are graphene and carbon nanotubes [24], while the typical metals include Au [25], Pt [26], Ag [27], etc. Careful observation towards the modification approaches reveals that drop-coating is the most common way of material decoration on sensing interface, and electrical deposition comes next. However, the former method may cause uneven dispersion and shedding of nanomaterials, resulting in poor reproducibility and instability; the latter suffers from limited applicability to certain materials [28]. ...
Article
Full-text available
A novel electrochemical sensor based on dual-template molecularly imprinted polymer (MIP) with nanoporous gold leaf (NPGL) was established for the simultaneous determination of dopamine (DA) and uric acid (UA). NPGL acts as an enlarged loading platform to enhance sensing capacity, and the MIP layer was synthesized in situ in the presence of monomer and dual templates (DA and UA) to provide specific recognition. Under the optimal conditions, the sensor shows a good linear range of 2.0~180 μM for DA at a working potential of 0.15 V (vs. Ag/AgCl) and 5.0~160 μM for UA at 0.35 V (vs. Ag/AgCl), with the respective detection limit of 0.3 μM and 0.4 μM (S/N = 3). Good selectivity of the sensor to its dual templates was confirmed as the sensing signals are significantly different between templates and interfering species. The responses maintained higher than 96% of the initial values after 30-day storage, and the day-to-day relative standard deviation is less than 3.0%. Real sample simultaneous determination of DA and UA was conducted with bovine serum, and the results were in good agreement with those from high-performance liquid chromatography. It can be concluded that this work offers a reliable, facile, fast, and cost-effective method of simultaneous quantification of two or more chem-/bio-molecules. Graphical abstract
... Thus, we proposed a mechanism based on a complex polymerization of aromatic amine compounds as reported. [16,[52][53][54][55] In short, three mechanisms can be proposed: (i) ...
Article
In the last years, the study of the formation of a polymer containing multidentate Schiff-base ligand as subunits has been performed. In general, the electropolymerization occurs through the interaction between the phenyl rings and metallic centers. However, in this paper, we proposed a new polymeric thin film formation from 2,2'-[1,2-ethanediylbis(nitrilomethylidyne)]bis[4-amino-phenol] obtained by electropolymerization. The electropolymerization mechanism for poly(phenazine-salen) formation was based on the carbon-nitrogen coupling. The effect of experimental parameters such as scan rate, applied potential range, supporting electrolyte, and solvent type on the electropolymerization process was also evaluated. The poly(phenazine-salen) film was characterized by cyclic voltammetry and electrochemical impedance spectroscopy in an inert supporting electrolyte showing a redox couple ascribed to pyrazine moieties. The Mott-Schottky plot of the electropolymerized material indicated that the polymer is an n-type semiconductor. The results indicate a polymeric formation controlled by the electropolymerization parameters and the electrochemical behavior tuned by the ions insertion/extraction from supporting electrolyte.
... This actuation can be followed in two different ways, including monitoring of (i) the increase of the R ct by EIS and (ii) the rise in porosity and the rate of the redox probe diffusion by DPV. Previously reported MIP chemosensors revealed a similar increase of both the EIS and DPV signal with the analyte concentration increase [48,49]. ...
Article
Fumonisin B1 (FB1) is a carcinogenic mycotoxin contaminating food and animal feed. Although the sensitivity of chromatography and immunoassays is high for FB1 determination, these techniques are still involved, challenging to be portabilised, laborious, and costly. Herein, a highly sensitive and selective electrochemical sensor using molecularly imprinted polymer nanoparticles (nanoMIPs) for FB1 recognition was devised and fabricated. NanoMIPs were prepared by free-radical polymerisation using solid-phase synthesis and characterised by DLS, SPR, SEM and FTIR spectroscopy. The chemosensor was prepared in two steps; the first involved deposition by electropolymerisation of a polypyrrole conducting film on a Pt electrode, and then nanoMIPs were covalently attached to this film imaged by AFM. Both electrochemical impedance spectroscopy (EIS) and differential pulse voltammetry (DPV) served for analytical signal transduction. The chemosensor sensitivities were 0.442 kΩ/pM (R² = 0.98) and 0.281 µA/pM (R² = 0.96) in the concentration range of 1 fM to 10 pM FB1. The limit of detection was impressively low equality to 0.03 and 0.7 fM. While the DPV determined imprinting factor was appreciable high 6.28. This electrochemical sensor also has a high recovery percentage of 96 - 102% in FB1 spiked maize and no cross-reactivity to other mycotoxins. Thus, the chemosensor proved useful as an effective alternative tool for FB1 determination in maize.
... A novel molecularly imprinted polymer (MIP) sensor was developed by Motia et al. (2018) for the electrochemical detection of sodium lauryl sulfate (SLS). ...
Chapter
Nowadays the presence of numerous emerging micropollutants is one of the most challenging problems in the aquatic environments. Their occurrence in water bodies is due to continuous discharge of personal care products (PCPs) into the environment and developed analytical techniques. Their entering to wastewater treatment plants (WTP or WWTP) has the negative effects on biological treatment processes; therefore conventional treatment processes are unable to completely remove PCPs from aquatic environments. This chapter reviews the acute and chronic toxicity data available for PCPs and focuses on the occurrence and fate of PCPs in water bodies and the techniques adopted for their removal from sewage treatment plant/WTP unit in different countries. The purpose of this chapter is to provide a comprehensive summary of the removal and fate of PCPs in aquatic environments to adopt optimal methods for their removal in water and WWTP.
... A novel molecularly imprinted polymer (MIP) sensor was developed by Motia et al. (2018) for the electrochemical detection of sodium lauryl sulfate (SLS). ...
Chapter
Use of surfactants is increasing day by day, and it has created a lot of water and soil pollutions all over the globe. Majority of surfactants are not biodegradable, and therefore it is likely to reach an alarming situation, if not controlled timely. As it is used in a wide range of products like detergents, shampoos, floor cleaning liquids, cosmetic products, etc., its use cannot be completely checked. Here the problem related to its excess in environment, classification in various types, etc. has been discussed along with its detection or determination in different samples of water and soil. Apart from it various attempts that have been made to either degrade or to remove different nonbiodegradable surfactants have also been summarized.
... A novel molecularly imprinted polymer (MIP) sensor was developed by Motia et al. (2018) for the electrochemical detection of sodium lauryl sulfate (SLS). ...
Chapter
Although the unique global increase of pharmaceuticals is referred to one of the greatest benefits of health in society, it has also been paralleled by discharge of these compounds in natural environment and ecosystem. Knowledge concerning the fate, occurrence, and adverse effects of remained pharmaceutical in the aquatic environments is very low. Wastewater treatment plants have been identified as a major way for discharge of pharmaceuticals in aquatic bodies (ranging from ng/L to μg/L). Pharmaceuticals classes include nonsteroidal antiinflammatory drugs, psychiatric, cardiovascular, hypocholesterolemic drugs, steroid hormones, and antibiotics. Currently due to their continuous discharge into the aquatic media and possible adverse health effects on human, flora, biota, and aquatic ecosystems, pharmaceuticals as emerging trace pollutants have obtained growing attention. First during the Catchment Quality Control in USA, it was found that pharmaceutical compounds can enter the water bodies. Although, for safety and efficacy aspects, strict regulations and controls are derived by pharmaceutical companies and institutions such as Food and Drug Administration or the European Medicines Agency (EMA), there are many environmental challenges to face now and in the future. Despite a great scientific advancement has been achieved, our knowledge is still limited on pharmaceuticals behavior as emerging micropollutants in aquatic environments. This review will be helpful to reveal the environmental exposure to these compounds in the aquatic environments.
... The progress of MIPs, as a selective sorbent, has been extensively studied in the field of environmental [6][7][8][9][10], food [11][12][13][14][15], biological [16][17][18][19] and pharmaceuticals [20][21][22]. MIPs are employed as a pre-concentration technique in extraction, synthesis, and characterization from different matrices. ...
Article
Sample preparation techniques have always been considered as a complex issue in the analytical process. Most of the sample preparation techniques show a lack of selectivity. Molecularly imprinted polymer (MIP) is a synthetic approach for sample preparation technique that has the ability of selective extractions. Generally, MIPs are selective sorbent, MIPs are capable of binding a molecule or its geometrical analogues. The imprinted polymers own particular voids exclusively framed for the aimed target analytes. These MIPs have been synthesized through a complex route of polymerization using a dedicated crosslinker, a template and function bound specific monomers (mainly interacting with the template). Despite having various pros like selectivity, morphological predictability, chemical & thermal stability, points alike binding site heterogeneity, partial template removal, and limited application pose a challenge. In this regard, a relatively newer carbon-based MIP method is explored as the molecular imprinting technique in various environmental samples. This paper describes the current scenario in the field of molecular-based imprinting technology using different carbon engrained materials and highlights the latest applications in this field and suggest proposals for the prospect in the area of the MIP.
... Log C -0.002, respectively. The LOD is calculated using LOD = 3 S b/m, where Sb is the standard deviation of the y-intercept of the regression line and m is the slope of the calibration curve, based on signal-to-noise ratio (S/N = 3) [37][38][39]. For the DPV technique, good linearity (R 2 = 0.99) is observed over the study range with analytical parameters, such as sensitivity, LOD and LOQ of 0.58 mL/μg, 0.001 μg/mL and 0.025 μg/mL, respectively. ...
Article
A molecularly imprinted electrochemical sensor was fabricated for sensitive and selective detection of anti-COVID 19 drug favipiravir (FAV). The sensor is based on the synthesis of biomass-derived carbon (BC) and nickel disulfide nanospheres (NiS2 NS), which were used to decorate glassy carbon electrode (GCE). Then, the gold nanoparticles (AuNPs) were electro- deposited on the surface of NiS2 NS/BC/GCE to enhance conductivity, increase electron transfer, and aid polymerization of p-aminothiophenol (p-ATP) functional monomer. The fabrication steps were characterized using different morphological and electrochemical techniques. Variables affecting the formation of molecularly imprinted layers and the determination of FAV were optimized. Under optimum conditions, the oxidation current (Ipa) was increased upon addition of FAV in the range of 0.42-1100 nM with a limit of detection (LOD, S/N) of 0.13 nM. The as-fabricated sensor possesses several advantages such as high sensitivity and selectivity, good reproducibility, and acceptable stability. Furthermore, the proposed molecularly imprinted –based electrochemical sensor was efficiently applied for the determination of FAV in tablets and human serum samples with recoveries % of 99.2 to 102.1 % and RSDs % in the range of 2.4-3.2 %, which confirms the reliability of the sensor to detect FAV in different matrices.
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Linear alkyl sulfates are a major class of surfactants that have large-scale industrial application and thus wide environmental release. These organic pollutants threaten aquatic environments and other environmental compartments. We show the promise of the use of a whole-cell electric sensor in the analysis of low or residual concentrations of sodium dodecyl sulfate (SDS) in aqueous solutions. On the basis of bioinformatic analysis and alkylsulfatase activity determinations, we chose the gram-negative bacterium Herbaspirillum lusitanum, strain P6–12, as the sensing element. Strain P6–12 could utilize 0.01–400 mg/L of SDS as a growth substrate. The electric polarizability of cell suspensions changed at all frequencies used (50–3000 kHz). The determination limit of 0.01 mg/L is much lower than the official requirements for the content of SDS in potable and process water (0.5 and 1.0 mg/L, respectively), and the analysis takes about 1–5 min. The promise of H. lusitanum P6–12 for use in the remediation of SDS-polluted soils is discussed. Graphical abstract
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Triclosan (TCS) is an antifungal and antimicrobic component used in various cosmetic, healthcare, and personal care products; therefore, many people are exposed to this compound. Literature and related studies have shown inflammatory skin conditions and endocrine disruption after exposure to TCS. Low concentrations of TCS released into environmental wastewater and soil eventually increase the toxicity. Hence, the detection and sensing of TCS is an important process. Nanostructured semiconductor materials are widely used for the selective and sensitive sensing of TCS because of their high accuracy, wide linear range, and high conductivity. This Review describes the progress made in the use of nanostructured particles such as metal oxides and metal oxide nanocomposite, multiwalled carbon nanotubes (MWCNTs), carbon nanodots (CNDs), graphene, molecular imprinted polymers (MIPs), organic polymers, polymer nanocomposite, quantum dots (QDs), gold nanoparticles, silver nanoparticles, and other nanoparticles as electrode active materials for the electrochemical sensing of TCS in environmental samples. Safety concern: This Review describes progress in the use of nanostructured particles as electrode active materials for the electrochemical sensing of triclosan in environmental samples.
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The foremost objective of this work is to prepare a novel electrochemical sensor-based screen-printed carbon electrode made of zinc oxide nanoparticles/molecularly imprinted polymer (SPCE–ZnONPs/MIP) and investigate its characteristics to detect sodium dodecyl sulfate (SDS). The MIP that is polyglutamic acid (PGA) film was synthesized via in situ electro-polymerization. The SDS's recognition site was left on the surface of the PGA film after extraction using the cyclic voltammetry (CV) technique, facilitating the specific detection of SDS. Moreover, the ZnONPs (∼71 nm, polydispersity index of 0.138) were synthesized and effectively combined with the MIP by a drop-casting method, enhancing the current response. The surface of the prepared SPCE–ZnONPs/MIP was characterized by scanning electron microscopy and energy dispersive X-ray. Besides, the electrochemical performance of the SPCE–ZnONPs/MIP was also studied through CV and differential pulse voltammetry (DPV) techniques. As an outstanding result, it is observed that the current response of SPCE–ZnONPs/MIP for detection of SDS remarkably increased almost four times higher from 0.009 mA to 0.041 mA in comparison with bare SPCE. More importantly, the proposed SPCE–ZnONPs/MIP exhibited an excellent selectivity (in the presence of interfering molecules of Ca2+, Pb2+, as well as sodium dodecylbenzene sulfonate (SDBS)), sensitivity, reproducibility, and repeatability. Since the modified sensor offers portability, it is suitable for in situ environment and cosmetic monitoring.
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Molecular imprinted polymers are custom made materials with specific recognition sites for a target molecule. Their specificity and the variety of materials and physical shapes in which they can be fabricated make them ideal components for sensing platforms. Despite their excellent properties, MIP-based sensors have rarely left the academic laboratory environment. This work presents a comprehensive review of recent reports in the environmental and biomedical fields, with a focus on electrochemical and optical signaling mechanisms. The discussion aims to identify knowledge gaps that hinder the translation of MIP-based technology from research laboratories to commercialization.
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Per- and polyfluoroalkyl substances (PFAS) are an emerging class of pervasive and harmful environmental micropollutant with negative health effects on humans. Therefore, there has been extensive research into the remediation (i.e., the detection, extraction, and destruction) of these chemicals. For efficient extraction and destruction, PFAS contamination must be detected at its onset; however, conventional PFAS detection methods rely on sample collection and transport to a centralized facility for testing, which is expensive and time-consuming. Electrochemistry offers a robust, inexpensive, and deployable sensing strategy that could detect pollution at its onset; however, the electrochemical inactivity of PFAS necessitates the use of a surface functionalization strategy. Molecularly imprinted polymers (MIPs), which are a popular surface functionalization strategy, have been around since the 1980s for specific electrochemical detection and have expanded electrochemical detection to analytes that are not electrochemically active. MIPs have been more recently demonstrated for the detection of a variety of PFAS species, but additional advances must be made for realization of a deployable, electrochemical MIP-based sensor. This Feature highlights the history of MIPs for PFAS detection and our group's recent advances that are essential to enable the creation of a deployable electrochemical PFAS sensor: development of rigorous analytical standards to quantify interferent effects, miniaturization of the detection platform for quantification in river water, the use of ambient O2 as the mediator molecule for detection, and the development of hardware for in-field multiplexed electrochemical sensing.
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This research work deals with the diphenyl phosphate (DPP) detection in urine samples using a molecularly imprinted polymer (MIP) sensor and a voltammetric electronic tongue (VE-tongue). In this regard, gold nanoparticles (Au-NPs) and titanium dioxide (TiO2) were first designed onto a screen-printed carbon electrode (SPCE). Then, the MIP sensor was fabricated by bulk-polymerization of methacrylic acid and DPP molecules as template. Cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), differential pulse voltammetry (DPV), atomic force microscopy (AFM) and Fourier transform infrared spectroscopy (FTIR) techniques were used in the help of sensor characterizations. With the intention to achieve a sensor with the maximum performance, the important experimental parameters were optimized. The sensor revealed good selectivity toward interferents, to be specific, 1-naphthyl phosphate and triethyl phosphate. It exhibited good linearity over a range from 0.1 ng/mL to 24.3 ng/mL. Unprecedented, the good reproducibility, stability, high sensitivity (0.141 mL/ng), low limits of detection (LOD = 0.063 ng/mL) and quantification (LOQ = 2.12 ng/mL) were achieved. The MIP sensor exhibited good results in term of real DPP determination in urine samples from nail polish users with a relative standard deviation (RSD less than 4%). Secondly, qualitative analysis was carried out by using a VE-tongue combined with chemometric approaches to classify urine samples. Partial least squares (PLS) method supplied prediction models achieved from the both systems data with a regression coefficient (R2=0.99). Taking into account the outcomes, the MIP sensor and the VE-tongue can constitute a good vista for others applications in cosmetic field.
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The ever-increasing presence of contaminants in environmental waters is an alarming issue, not only because of their harmful effects in the environment but also because of their risk to human health. Pharmaceuticals and pesticides, among other compounds of daily use, such as personal care products or plasticisers, are being released into water bodies. This release mainly occurs through wastewater since the treatments applied in many wastewater treatment plants are not able to completely remove these substances. Therefore, the analysis of these contaminants is essential but this is difficult due to the great variety of contaminating substances. Facing this analytical challenge, electrochemical sensing based on molecularly imprinted polymers (MIPs) has become an interesting field for environmental monitoring. Benefiting from their superior chemical and physical stability, low-cost production, high selectivity and rapid response, MIPs combined with miniaturized electrochemical transducers offer the possibility to detect target analytes in-situ. In most reports, the construction of these sensors include nanomaterials to improve their analytical characteristics, especially their sensitivity. Moreover, these sensors have been successfully applied in real water samples without the need of laborious pre-treatment steps. This review provides a general overview of electrochemical MIP-based sensors that have been reported for the detection of pharmaceuticals, pesticides, heavy metals and other contaminants in water samples in the past decade. Special attention is given to the construction of the sensors, including different functional monomers, sensing platforms and materials employed to achieve the best sensitivity. Additionally, several parameters, such as the limit of detection, the linear concentration range and the type of water samples that were analysed are compiled.
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A molecularly imprinted electrochemical sensor for high recognition of 2,4,6-trichlorophenol based on molecular imprinted polymers (MIPs) was successfully constructed. The sensitive and selective layer was Ag nanoparticles-polydopamine-reduced graphene oxide modified glassy carbon electrode (AgNPs-PDA-GR/GCE), which was following coupled with electro-polymerization of o-phenylenediamine (o-PD) on the surface of AgNPs-PDA-GR/GCE in the presence of 2,4,6-trichlorophenol as a template molecule. Due to the enhanced electron transfer rate of AgNPs-PDA-GR composites, the specific recognition of imprinted cavities, as well as the strong π–π stacking and hydrogen bonding between PDA-graphene and 2,4,6-TCP, MIPs/AgNPs-PDA-GR/GCE showed highly sensitive and selective recognition for 2,4,6-TCP. The electrochemical responses of imprinted sensor presents two dynamic linear relationships across the range of 2.0 ~ 10.0 nM and 10.0 ~ 100.0 nM with a detection limit of 0.7 nM. Further, the concentration of 2,4,6-TCP in water was determined by MIPs/AgNPs-PDA-GR/GCE and the recovery was about 96.4 ~ 103.3%. This study provides a new platform and design concept for the quantitative analysis of 2,4,6-TCP in real samples.
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Inflammatory diseases increase has recently sparked the research interest for drugs diagnostic tools development. At therapeutic doses, acetylsalicylic acid (ASA or aspirin) is widely used for these diseases' treatment. ASA overdoses can however give rise to adverse side effects including ulcers, gastric damage. Hence, development of simple, portable and sensitive methods for ASA detection is desirable. This paper reports aspirin analysis in urine, saliva and pharmaceutical tablet using an electrochemical sensor and a voltammetric electronic tongue (VE-Tongue). The electrochemical sensor was fabricated by self-assembling chitosan capped with gold nanoparticles (Cs + AuNPs) on a screen-printed carbon electrode (SPCE). It exhibits a logarithmic-linear relationship between its response and the ASA concentration in the range between 1 pg/mL and 1 μg/mL. A low detection limit (0.03 pg/mL), good selectivity against phenol and benzoic acid interference, and successful practical application were demonstrated. Qualitative analysis was performed using the VE-Tongue based unmodified metal electrodes combined with two chemometric approaches to classify urine samples spiked with different aspirin concentrations. Partial least squares (PLS) method provided prediction models obtained from the data of both devices with a regression correlation coefficient R2 = 0.99. Correspondingly, the SPCE/(Cs + AuNPs) electrochemical sensor and VE-Tongue could be viable tools for biological analysis of drugs.
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Diabetes mellitus (DM) is often diagnosed by invasive or enzymatic methods being progressively somewhat undesirable. If salivary glucose (SG) level correlates with blood glucose (BG), it could be useful for early DM detection. In this work, a molecular imprinted polymer (MIP) approach was used to develop an electrochemical non-enzymatic sensor to determine SG in micro-molar levels. The MIP based Screen printed gold electrode (Au-SPE) was prepared by electropolymerizing Acrylamide/Bis-Acrylamide (AAM/NNMBA) in the presence of glucose (G) as a template. The Cyclic voltammetry (CV), differential pulse voltammetry (DPV) and electrochemical impedance spectroscopy (EIS) techniques were employed for the electrochemical measurements with Ferri/Ferrocyanide as redox probe in phosphate buffer saline. Morphological characterizations of the elaborated sensors were performed by using atomic force microscopy (AFM) and scanning electron microscopy coupled with energy dispersive X-ray spectroscopy (SEM-EDS). Important parameters influencing the MIP sensor performances such as extraction, incubation time, potential range and number of CV cycles, were studied and optimized. Under optimum conditions, the sensor could effectively detect glucose avoiding interferences of structural similar substances like lactose and sucrose. In a working range from 0.5 to 50 μg/mL, it exhibits a detection and quantification limits of 0.59 μg/mL and 1.9 μg/mL, respectively. Additionally, the real saliva glucose determination was compared to those of finger prick blood with satisfactory results (R² = 0.99) by using partial least squares (PLS) statistical technique. Correspondingly, this work has demonstrated a cheap, simple and effective sensing platform for non-enzymatic glucose detection thus making it a promising tool for future evolution of accurate and reliable non-invasive DM diagnosis.
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Doxycycline (DXy) is a cycline antibiotic, most frequently prescribed to treat bacterial infections in veterinary medicine. However, its broad antimicrobial activity and low cost, lead to an intensive use, which can seriously affect human health. Therefore, its spread in the food products has to be monitored. The scope of this work was to synthetize a sensitive and very selective molecularly imprinted polymer (MIP) for DXy detection in honey samples. Firstly, the synthesis of this biosensor was performed by casting a layer of carboxylate polyvinyl chloride (PVC-COOH) on the working surface of a gold screen-printed electrode (Au-SPE) in order to bind covalently the analyte under mild conditions. Secondly, DXy as a template molecule was bounded to the activated carboxylic groups, and the formation of MIP was performed by a biocompatible polymer by the mean of polyacrylamide matrix. Then, DXy was detected by measurements of differential pulse voltammetry (DPV). A non-imprinted polymer (NIP) prepared in the same conditions and without the use of template molecule was also performed. We have noticed that the elaborated biosensor exhibits a high sensitivity and a linear behavior between the regenerated current and the logarithmic concentrations of DXy from 0.1 pg.mL−1 to 1000 pg.mL−1. This technic was successfully applied to determine DXy residues in honey samples with a limit of detection (LOD) of 0.1 pg.mL−1 and an excellent selectivity when compared to the results of oxytetracycline (OXy) as analogous interfering compound. The proposed method is cheap, sensitive, selective, simple, and is applied successfully to detect DXy in honey with the recoveries of 87% and 95%. Considering these advantages, this system provides a further perspective for food quality control in industrial fields.
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Sulfonamides are antimicrobial drugs which are widely used in human and veterinary medicine but pose a potential risk as emerging pollutants when present even at low concentrations in soil or water. Therefore, the development of analytical tools for sulfonamide monitoring is needed. Electrochemical methods have been commonly reported for sulfonamide detection. Here are reported recent developments related to the use of electrochemical detection of sulfonamides from 2006 to 2016. A discussion of sulfonamide detection is provided for pharmaceutical formulations, biological fluids, food, and environmental samples. In addition to the developed electrochemical methods, a brief review of sulfonamide sample preparation is also included. KEYWORDS: electrochemical sensors, environmental monitoring, food, pharmaceutical formulation, sulfonamides
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In this article, three-dimensional (3D) microstuctured poly(3, 4-ethylenedioxythiophene) (PEDOT)/reticulated vitreous carbon (RVC) composite electrodes with varying amount of PEDOT loadings were successfully prepared by electrochemical deposition method. The composites were characterized by Raman spectroscopy, thermogravimetric analysis (TGA), scanning electron microscopy (SEM), and cyclic voltammetry. Raman spectra suggest that there is a strong interaction between the RVC and backbone of PEDOT chain. It is revealed from the SEM images that the PEDOT amount, thickness, surface roughness, porosity, and globular structure on RVC electrode are increased with the increase in polymerization time. The capacitance of PEDOT/RVC electrode has increased by a factor of 2230 compared to a bare RVC electrode when polymerization is carried out for 120 min. Moreover, the capacitance of PEDOT was found to be very high compared with other PEDOT studies. The electrodes also show good cyclic stability. This substantial increase in capacitance of RVC electrode is due to the rough, highly porous, and honeycomb-like fine structure of PEDOT coating, which shows a flower-like morphology, consisting of numerous thin flakes with numbers of macropores and micropores. This interesting morphology has enhanced the performance of PEDOT because of increased electrode surface area, specific capacitance, and macroporous structure of RVC electrode.
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Detecting cancer disease at an early stage is one of the most important issues for increasing the survival rate of patients. Cancer biomarker detection helps to provide a diagnosis before the disease becomes incurable in later stages. Biomarkers can also be used to evaluate the progression of therapies and surgery treatments. In recent years, molecularly imprinted polymer (MIP) based sensors have been intensely investigated as promising analytical devices in several fields, including clinical analysis, offering desired portability, fast response, specificity, and low cost. The aim of this review is to provide readers with an overview on recent important achievements in MIP-based sensors coupled to various transducers (e.g., electrochemical, optical, and piezoelectric) for the determination of cancer biomarkers by selected publications from 2012 to 2016.
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The present study investigated the intertissue differences in genotoxicity induction in the fish, Channa punctatus, in response to 4-nonylphenol. The lethal concentration of 50 (LC50) was estimated using a semi-static system. Fish were subjected to three sublethal concentrations of 4-nonylphenol (NP) for 24, 48, 72, and 96 h. Liver, gill, and kidney tissues were analyzed, and the genotoxicity was estimated using the micronucleus test and the comet assay. The frequency of micronucleated cells (MNCs), binucleated cells (BNCs), aberrant cells, and tail moment (TM) increased significantly. The time for maximum induction of genotoxicity for all the parameters considered in the micronucleus assay was 72 h of exposure, whereas the TM was highest at 24 h of exposure followed by a decline. The gill and liver showed higher genotoxicity than kidney tissue demonstrating organ-specific susceptibilities to NP in fish C. punctatus.
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A sensitive electrochemical molecularly imprinted sensor was developed for the detection of glyphosate (Gly), by electropolymerisation of p-aminothiophenol-functionalised gold nanoparticles in the presence of Gly as template molecule. The extraction of the template leads to the formation of cavities that are able to specifically recognise and bind Gly through hydrogen bonds between Gly molecules and aniline moieties. The performance of the developed sensor for the detection of Gly was investigated by linear sweep voltammetry using a hexacyanoferrate/hexacyanoferrite solution as redox probe, the electron transfer rate increasing when concentration of Gly increases, due to a p-doping effect. The molecularly imprinted sensor exhibits a broad linear range, between 1 pg/L and 1 µg/L and a quantification limit of 0.8 pg/L. The selectivity of the proposed sensor was investigated towards the binding of Gly metabolite, aminomethylphosphonic acid, revealing excellent selectivity towards Gly. The developed sensor was successfully applied to detect Gly in tap water samples.
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An amperometric screening method for the control of sulfonamides in different matrices has been developed. The detection was improved by using multiwalled carbon nanotubes-glassy carbon electrodes (MWCNTs-GCE). Six representative sulfonamides (SAAs), namely, sulfanilamide, sulfaguanidine, sulfamerazine, sulfisoxazole, sulfathiazole and sulfadiazine were selected for this purpose. Statistical analysis of the obtained data demonstrated that this type of modified electrodes presented considerably better stability and sensitivity than the conventional unmodified ones. Detection limits were in the 0.01 and 0.04 μg mL−1 range, whereas quantification limits were between 0.05 and 0.1 μg mL−1. The usefulness of the method was demonstrated by the analysis of different types of samples. Particularly interesting is the application to milk samples, where the European legislation establishes a maximum residue level for SAAs at 0.1 μg mL−1. The developed method was demonstrated to be a good alternative screening method for this threshold of reference, with an unreliability zone of between 0.05 and 0.09 μg mL−1, which is useful for the reliable classification of milk samples.
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Antimicrobial resistance is a global public health challenge, which has accelerated by the overuse of antibiotics worldwide. Increased antimicrobial resistance is the cause of severe infections, complications, longer hospital stays and increased mortality. Overprescribing of antibiotics is associated with an increased risk of adverse effects, more frequent re-attendance and increased medicalization of self-limiting conditions. Antibiotic overprescribing is a particular problem in primary care, where viruses cause most infections. About 90% of all antibiotic prescriptions are issued by general practitioners, and respiratory tract infections are the leading reason for prescribing. Multifaceted interventions to reduce overuse of antibiotics have been found to be effective and better than single initiatives. Interventions should encompass the enforcement of the policy of prohibiting the over-the-counter sale of antibiotics, the use of antimicrobial stewardship programmes, the active participation of clinicians in audits, the utilization of valid rapid point-of-care tests, the promotion of delayed antibiotic prescribing strategies, the enhancement of communication skills with patients with the aid of information brochures and the performance of more pragmatic studies in primary care with outcomes that are of clinicians' interest, such as complications and clinical outcomes.
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The construction and characteristic performance of a new potentiometric PVC membrane sensor responsive for sodium dodecyl sulfate (SDS) are described. The sensor is based on the use of cetyltrimethylammonium-tetraphenylborate (CTA-TPB) ion-pair complex as electroactive material in PVC matrix in presence of dioctyl phthalate as a solvent mediator. The sensor exhibits a rapid, stable and near-Nernstian response for SDS over the concentration range of 5 × 10−3–5 × 10−6 mol dm−3 at 25 ± 2 °C and the pH range 4–8.5 with slope of 59.6 mV/decade change in SDS concentration. The lower detection limit is 5 × 10−6 mol dm−3 and the response time is 45 s. The determination of selectivity coefficients for different anions shows there is no interference except that of dodecyl benzene sulfonate (DBS−) ion which has a strong interference. The results obtained in the determination of SDS in toothpastes, using this sensor as an indicator electrode, were compared with those obtained from the spectrophotometric method using methylene blue as the reagent.
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Honey produced by honeybees is a valuable food product. The presence of xenobiotics in honey may harm its quality and constitute a danger to human health. Antibiotics are commonly applied by beekeepers to eliminate disease among honeybees. Moreover, ubiquitous administration of antibiotics may cause bacteria to become resistant to many drugs and spread antibiotic-resistant strains of bacteria. Appropriate sample preparation and determination of antibiotics at very low concentrations in foodstuffs are real analytical challenges. This article reviews analytical methods used for determination of residues of different sorts of antibiotic in honey and other honeybee products.
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The electrochemical properties of sulfaguanidine (Sg) is investigated in detail at a glassy carbon electrode (GCE) modified with a multi-walled carbon nanotube (MWCNT). Cyclic voltammetry and chronoamperometry were used as diagnostic techniques. The MWCNT-GCE exhibited excellent electrocatalytic behavior for the oxidation of Sg as evidenced by the enhancement of the 2e-oxidation peak current and the shift in the oxidation potential to less positive values (by 90 mV) in comparison with a bare GCE. A detailed analysis of cyclic voltammograms and chronoamprograms gave fundamental electrochemical parameters including the electroactive surface coverage (Γ), the transfer coefficient (α), the heterogeneous rate constant (k s) and the diffusion coefficient (D). Under the selected conditions, the peak current shows two dynamic linear ranges10-100 μM and 100-1000μM with the detection limit of 10μM. The method was successfully applied to analyze Sg in urine and serum samples.
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Bee products can be contaminated from different sources. The contamination can arise from beekeeping practices or from the environment. Environmental contaminants are covered in the first part of the review. They are: the heavy metals lead, cadmium and mercury, radioactive isotopes, organic pollutants, pesticides (insecticides, fungicides, herbicides and bactericides), pathogenic bacteria and genetically modified organisms. The second part of the review discusses contaminants from beekeeping. The main ones are acaricides: lipophylic synthetic compounds and non-toxic substances such as organic acids and components of essential oils; and antibiotics used for the control of bee brood diseases, mainly tetracyclines, streptomycine, sulfonamides and chloramphenicol. Other substances used in beekeeping play a minor role: para-dichlorobenzene, used for the control of wax moth and chemical repellents. The degree of contamination of honey, pollen, beeswax, propolis and royal jelly by the different contaminants is reviewed.
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A new, simple and sensitive spectrophotometric method for the determination of some sulfonamide drugs has been developed. The method is based on the diazotization of sulfacetamide, sulfadiazine, sulfaguanidine, sulfamerazine, sulfamethazine, sulfamethoxazole, and their coupling with 8-hydroxyquinoline in alkaline media to yield red coloured products with absorption maxima at 500 nm. Beer's law is obeyed from 0.1-7.0 microg mL-1. The limits of quantification and limits of detection were 0.11-0.18 and 0.03-0.05 microg mL-1, respectively. Intraday precision (RSD 0.1-0.5%) and accuracy (recovery 97.3--100.8%) of the developed method were evaluated. No interference was observed from common adjuvants. The method has been successfully applied to the assay of sulpha drug in pharmaceutical formulations.
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Sulfaguanidine (SG), belongs to the class of sulfonamide drug used as an effective antibiotic. In the present work, using crystal engineering approach two novel cocrystals of SG were synthesized (SG-TBA and SG-PT) with thiobarbutaric acid (TBA) and 1,10-phenanthroline (PT), characterized by solid state techniques viz., powder X-ray diffraction (PXRD), fourier transform infrared spectroscopy (FT-IR), differential scanning calorimetry (DSC) and the crystal structures were determined by single crystal X-ray diffraction studies. A comparative antibacterial activity and hemolytic potential was done on SG drug, coformers and their cocrystals. The tested cocrystals formulations showed almost two fold higher antibacterial activity against the tested strains of bacteria Gram-positive bacteria (S. mutans and E. faecalis) and Gram-negative bacteria (E. coli, K. pneumonia and E. clocae) over SG alone and their coformers. Cocrystal SG-TBA showed better antibacterial activity and reduced hemolysis, thereby, reduced cytotoxicity than SG-PT.
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Fluorescent sensory MIP (molecularly imprinted polymer) particles were combined with a droplet-based 3D microfluidic system for the selective determination of a prototype small-molecule analyte of environmental concern, 2,4-dichlorophenoxyacetic acid or 2,4-D, at nanomolar concentration directly in water samples. A tailor-made fluorescent indicator cross-linker was thus designed that translates the binding event directly into an enhanced fluorescence signal. The phenoxazinone-type cross-linker was co-polymerized into a thin MIP layer grafted from the surface of silica microparticles following a RAFT (reversible addition-fragmentation chain transfer) polymerization protocol. While the indicator cross-linker outperformed its corresponding monomer twin, establishment of a phase-transfer protocol was essential to guarantee that the hydrogen bond-mediated signalling mechanism between the urea binding site on the indicator cross-linker and the carboxylate group of the analyte was still operative upon real sample analysis. The latter was achieved by integration of the fluorescent core-shell MIP sensor particles into a modular microfluidic platform that allows for an in-line phase-transfer assay, extracting the analyte from aqueous sample droplets into the organic phase that contains the sensor particles. Real-time fluorescence determination of 2,4-D down to 20 nM was realized with the system and applied for the analysis of various surface water samples collected from different parts of the world.
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A new detector, silvering detection window and in-capillary optical fiber light-emitting diode-induced fluorescence detector (SDW-ICOF-LED-IFD), is introduced for capillary electrophoresis (CE). The strategy of the work was that half surface of the detection window was coated with silver mirror, which could reflect the undetected fluorescence to the photomultiplier tube to be detected, consequently enhancing the detection sensitivity. Sulfonamides (SAs) are important antibiotics that achieved great applications in many fields. However, they pose a serious threat on the environment and human health when they enter into the environment. The SDW-ICOF-LED-IFD-CE system was used to determine fluorescein isothiocyanate (FITC)-labeled sulfadoxine (SDM), sulfaguanidine (SGD) and sulfamonomethoxine sodium (SMM-Na) in environmental water. The detection results obtained by the SDW-ICOF-LED-IFD-CE system were compared to those acquired by the CE with in-capillary optical fiber light-emitting diode-induced fluorescence detection (ICOF-LED-IFD-CE). The limits of detection (LODs) of SDW-ICOF-LED-IFD-CE and ICOF-LED-IFD-CE were 1.0–2.0 nM and 2.5–7.7 nM (S/N = 3), respectively. The intraday (n = 6) and interday (n = 6) precision of migration time and corresponding peak area for both types of CE were all less than 0.86% and 3.68%, respectively. The accuracy of the proposed method was judged by employing standard addition method, and recoveries obtained were in the range of 92.5–102.9%. The results indicated that the sensitivity of the SDW-ICOF-LED-IFD-CE system was improved, and that its reproducibility and accuracy were satisfactory. It was successfully applied to analyze SAs in environmental water.
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The aim of this study was to develop an analytical method for the analysis of a wide range of veterinary drugs in honey and royal jelly. A modified sample preparation procedure based on the quick, easy, cheap, effective, rugged and safe (QuEChERS) method was developed, followed by liquid chromatography tandem mass spectrometry determination. Use of the single sample preparation method for analysis of 42 veterinary drugs becomes more valuable because honey and royal jelly belong to completely different complex matrices. Another main advantage of the proposed method is its ability to identify and quantify 42 veterinary drugs with higher sensitivity than reference methods of China. This work has shown that the reported method was demonstrated to be convenient and reliable for the quick monitoring of veterinary drugs in honey and royal jelly samples.
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Sulfapyridine (SPy) is a sulfonamide antibiotic largely employed as veterinary drugs for prophylactic and therapeutic purposes. Therefore, its spread in the food products has to be restricted. Herein, we report the synthesis and characterization of a novel electrochemical biosensor based on gold microelectrodes modified with a new structure of magnetic nanoparticles (MNPs) coated with poly(pyrrole-co-pyrrole-2-carboxylic acid) (Py/Py-COOH) for high efficient detection of SPy. This analyte was quantified through a competitive detection procedure with 5-[4-(amino)phenylsulfonamide]−5-oxopentanoic acid-BSA (SA2-BSA) antigens toward polyclonal antibody (Ab-155). Initially, gold working electrodes (WEs) of integrated biomicro electro-mechanical system (BioMEMS) were functionalized by Ppy-COOH/MNPs, using a chronoamperometric (CA) electrodeposition. Afterward, SA2-BSA was covalently bonded to Py/Py-COOH/MNP modified gold WEs through amide bonding. The competitive detection of the analyte was made by a mixture of a fixed concentration of Ab-155 and decreasing concentrations of SPy from 50 µg L⁻¹ to 2 ng L⁻¹. Atomic Force Microscopy characterization was performed in order to ensure Ppy-COOH/MNPs electrodeposition on the microelectrode surfaces. Electrochemical measurements of SPy detection were carried out using electrochemical impedance spectroscopy (EIS). This biosensor was found to be highly sensitive and specific for SPy, with a limit of detection of 0.4 ng L⁻¹. This technique was exploited to detect SPy in honey samples by using the standard addition method. The measurements were highly reproducible for detection and interferences namely, sulfadiazine (SDz), sulfathiazole (STz) and sulfamerazine (SMz). Taking these advantages of sensitivity, specificity, and low cost, our system provides a new horizon for development of advanced immunoassays in industrial food control.
Article
Schiff bases synthesised from the condensation of 2-(hydroxy)naphthaldehyde and sulfonamides (sufathiazole (STZ), sulfapyridine (SPY), sulfadiazine (SDZ), sulfamerazine (SMZ) and sulfaguanidine (SGN)) are characterized by different spectroscopic data (FTIR, UV-Vis, Mass, NMR) and two of them, (E)-4-(((2-hydroxynaphthalen-1- yl)methylene)amino)-N-(thiazol-2-yl)benzenesulfonamide (1a) and (E)-N- (diaminomethylene)-4-(((2-hydroxynaphthalen-1-yl)methylene)amino)benzenesulfonamide (1e) have been confirmed by single crystal X-ray structure determination. Antimicrobial activities of the Schiff bases have been evaluated against certified and resistant Gram positive (S. aureus, E. facelis) and Gram negative (S. pyogenes, S. typhi, Sh dysenteriae, Sh. flexneri, K. pneumonia) pathogens. Performance of Schiff base against the resistant pathogens are better than standard stain and MIC data lie 32 – 128 µg/ml while parent sulfonamides are effectively inactive (MIC >512 µg/ml). The DFT optimized structures of the Schiff bases have been used to accomplish molecular docking studies with DHPS (dihydropteroate synthase) protein structure (downloaded from Protein Data Bank) to establish the most preferred mode of interaction. ADMET filtration, Cytotoxicity (MTT assay) and haemolysis assay have been examined for evaluation of druglike character.
Article
A multiclass method for screening and confirmatory analysis of antimicrobial residues in milk has been developed and validated. Sixty-two antibiotics belonging to ten different drug families (amphenicols, cephalosporins, lincosamides, macrolides, penicillin, pleuromutilins, quinolones, rifamycins, sulfonamides and tetracyclines) have been included. After the addition of an aqueous solution of EDTA, the milk samples were extracted twice with acetonitrile, evaporated and dissolved in ammonium acetate. After centrifugation, 10 μL were analysed using LC-Q-Orbitrap operating in positive electrospray ionization mode. The method was validated in bovine milk in the range 2-150 µg kg(-1) for all antibiotics; for four compounds with Maximum Residue Limits (MRLs) higher than 100 µg kg(-1) , the validation interval has been extended until 333 µg kg(-1) . The estimated performance characteristics were satisfactory complying with the requirements of Commission Decision 2002/657/EC. Good accuracies were obtained also taking advantage from the versatility of the hybrid mass analyser. Identification criteria were achieved verifying the mass accuracy and ion ratio of two ions, including the pseudomolecular one, where possible. Finally, the developed procedure was applied to thirteen real cases of suspect milk samples (microbiological assay) confirming the presence of one or more antibiotics, although frequently the MRLs were not exceeded. The availability of rapid multiclass confirmatory methods can avoid wastes of suspect, but compliant, raw milk samples.
Article
The manuscript presents the development of a new method for the quantification of 16 sulfonamides in beeswax. Different sample preparation techniques were tested and modified to maximise the recovery of the target analytes and minimise the amount of coeluted impurities under conditions that provide reproducible results. The proposed method consisted of melting and dilution of beeswax in a mixture of n-hexane and isopropanol followed by extraction with 2% acetic acid. The extract was cleaned up by solid-phase extraction using strong cation exchange phase. Determination of the sulfonamides was achieved by liquid chromatography coupled to tandem mass spectrometry with the use of a pentafluorophenyl analytical column and applying a gradient elution with acetonitrile and 0.01% acetic acid as mobile phases. The limits of detection and limits of quantification ranged from 1 to 2μg/kg and from 2 to 5μg/kg, respectively. The recoveries varied between 65.2% and 117.8% while coefficient of variation of the method was less than 24.2% under intermediate precision conditions. Finally, the method was applied to the analysis of real samples of beeswax from beekeepers and commercial foundations manufacturers.
Article
The vibrational wavenumbers of sulphaguanidine were calculated using Gaussian03 software at different levels and compared with experimentally observed data. The predicted infrared intensities, Raman activities and first hyperpolarizability are reported. The calculated geometrical parameters (DFT) are in agreement with that of similar derivatives. The potential energy scan studies for different torsion angles are also reported. The splitting of NH stretching wavenumber in the infrared spectrum indicates the weakening of the NH bond.
Article
A wide-scope screening methodology has been developed for the identification of veterinary drugs and pharmaceuticals in fish tissue and milk using Ultra-high Performance Liquid Chromatography Quadrupole Time-Of-Flight Mass Spectrometry (UHPLC-QTOF MS). The method was validated using a qualitative approach at two concentration levels. The detection of the residues was accomplished by retention time, accurate mass and the isotopic fit using an in-house database. Product-ion spectra were used for unequivocal identification of the compounds. Generic sample treatment was applied. The majority of the compounds were successfully detected and identified at a concentration level of 150 ng mL-1 in milk and 200 μg kg -1 in fish (more than 80% of the compounds in both matrices) while satisfactory results were also obtained at a concentration level of 15 ng mL-1 in milk and 20 μg kg -1 in fish (more than 60 % of the compounds detected and identified).
Article
A novel molecularly imprinted polymer (MIP) with high selectivity for sulfonamides was synthesized using reverisible addition fragmentation chain transfer (RAFT) polymerization technique with 2-cyanoprop-2-yl-dithionaphthalate as RAFT reagent, sulfadimethoxine as template, methacrylic acid (MAA) as functional monomer. The obtained MIP was characterized by static adsorption and the results indicated that the MIPs had high adsorption affinity to sulfonamides. The MIP was sucessfully empolyed as the adsorbtion sorbent of solid phase extraction for enrichment and clean-up four sulfonamides from food samples. Under the optimized conditions, good linearities were ranged from 0.010-10 µg/mL with r2≥0.9991.The recoveries at three spiked levels were ranged from 91.0-110.2% with RSD less than 5.8%.
Article
In this work, a novel electrochemical sensor for 3-chloro-1,2-propandiol (3-MCPD) detection based on a molecular imprinted polymer (MIP) film and a gold nanoparticles-modified glassy carbon electrode (AuNPs/GCE) was constructed. p-Aminothiophenol (p-ATP) and 3-MCPD were self-assembled on a AuNPs/GCE surface, and then a MIP film was formed by electropolymerization. 3-MCPD bonded with p-ATP during self-assembly and electropolymerization, and cavities that matched 3-MCPD remained after the removal of the template. The MIP sensor was characterized by cyclic voltammetry (CV), differential pulse voltammetry (DPV) and scanning electron microscopy (SEM). A number of factors that affected the activity of the imprinted film were optimized and discussed. Under optimal conditions, the peak current of 3-MCPD was linear to its concentration from 1.0×10-17 to 1.0×10-13 mol L-1 (R2 = 0.9939), and the detection limit was 3.8×10-18 mol L-1 (S/N = 3). The average recovery rate of 3-MCPD from spiked soy sauce samples ranged from 95.0% to 106.4% with a relative standard deviation of less than 3.49%. Practically, the sensor showed high sensitivity, good selectivity, reproducibility and stability during the quantitative determination of 3-MCPD.
Article
For high-throughput monitoring of the residues of sulfonamides (SAs) in edible animal tissues, a novel hapten and monoclonal-based indirect competitive enzyme-linked immunosorbent assay (ic-ELISA) was developed. The novel hapten was synthesized and conjugated to carrier protein as immunogen. The spleen cells of the inoculated mice expressing group-specificity against SAs were fused. The obtained monoclonal antibody 4E5 showed the cross-reactivity (CR) to 16 structurally different SAs. Based on this antibody, an optimised icELISA protocol was carried out with only phosphate-buffered saline for the fast extraction of SAs in the tissues. The limits of detection of SAs in chicken ranged from 1.5 to 22.3 μg kg−1. The recoveries were 70.6–121% with less than 24.1% relative standard deviation. The developed ic-ELISA showed a good correlation with high performance liquid chromatography. It would be a useful tool for the screening of residues of SAs in edible animal tissues.
Article
In this paper, we describe a compact and low-cost light-emitting diode-induced fluorescence (LED-IF) detection coupled to microchip electrophoresis for the determination of sulfonamides in pharmaceutical formulations and rabbit plasma. Three fluorescein isothiocyanate-labeled sulfonamides in rabbit plasma were separated in the running buffer of 40 mM phosphate buffer (pH 7.0) at the separation voltage of 2.0 kV, and detected by LED-IF detector in which the high-power blue LED was driven at the constant current of 150 mA and the emitted fluorescence over 510 nm was collected by a planar photodiode. The linear concentration ranged from 2.0 to 125.0 μg mL−1, both for sulfadiazine and sulfamethazine with the correlation coefficients (r 2) of 0.995 and 0.997, respectively, and from 2.0 to 100.0 μg mL−1 with the correlation coefficients (r 2) of 0.997 for sulfaguanidine. The limits of detection for the three sulfonamides were 0.36–0.50 μg mL−1 (S/N = 3). Intra-day and inter-day precision of migration time and peak area for the determination of sulfonamides were <4.5 %. This method has been successfully applied to the analysis of sulfonamides in pharmaceuticals, and could be used to study the pharmacokinetics of sulfonamides in rabbit.
Article
A novel electrochemical sensor for bovine hemoglobin (BHb) recognition and detection was prepared by a surface molecularly imprinted technique. Aldehyde group-functionalized silica microspheres were modified on an Au electrode surface, and these were subsequently covalently bound with the template molecule, BHb, through imine bonds. Electropolymerization was performed to deposit polypyrrole onto the above modified electrode surface. A three-dimensional macroporous structural sensor was obtained after etching of silica and the extraction of BHb. Differential pulse voltammetry (DPV) and electrochemical impedance spectroscopy (EIS) were employed to characterize the fabrication process of the sensor using [Fe(CN)6](3-)/[Fe(CN)6](4-) as an electroactive probe. Since all imprinted cavities were situated at the surface of the polymers, the prepared sensor exhibited considerably fast binding kinetics. Compared to other non-template proteins, the sensor showed an excellent recognition capacity for BHb. Moreover, the prepared sensor also exhibited a dependent relationship between the concentration of BHb and the peak current of [Fe(CN)6](3-)/[Fe(CN)6](4-).
Article
Sulfonamides (SAs) are one of the most frequently used antibiotics. SAs have been found in various environmental compartments. If SAs are not degraded in the environment, they can affect bacteria by their antibiotic properties and contribute to bacterial antibiotic resistance. Therefore, the biodegradability of 11 SAs (sulfanilamide, sulfaguanidine monohydrate, sulfadiazine, sulfathiazole, sulfapyridine, sulfamerazine, sulfamethoxypyridazine, sulfachloropyridazine, sulfamethazine, sulfamethoxazole, and sulfadimethoxine) was studied. For this purpose, the Closed Bottle Test (CBT, OECD 301D) was performed, which includes a toxicity control. In order to monitor the environmental fate of the parent compound and to check for transformation products, a simple, efficient, and reliable HPLC–UV method for the simultaneous determination of these SAs has been developed. Acetonitrile and water (with 0.1% formic acid) were used as mobile phase solvents for gradient elution. The method was validated in terms of precision, detection and quantitation limits, selectivity, and analytical solution stability. In the CBT, none of these SAs was readily biodegradable. The HPLC–UV analysis confirmed that no degradation of any SA took place. In the toxicity control, these SAs showed no toxic effect in the used concentration of environmental bacteria applied in the test.
Article
General tendencies of the progress in the development of electrochemical DNA sensors devoted to the determination of biologically active low-molecular compounds have been considered on the base on own authors investigations and literary data. The ways for the generation of analytical signal of DNA sensors are considered depending on the mechanism of DNA- analyte interaction. The application of DNA sensors for the determination of pharmaceuticals (anthracyclines,. phenothiazines, sulfonylamides etc.) and environmental pollutants is described. The prospects of DNA sensor development are discussed.
Article
A binding protein displaying broad-spectrum cross-reactivity within the sulfonamide group was used in conjunction with a sulfonamide specific sensor chip and a surface plasmon resonance biosensor to develop a rapid broad spectrum screening assay for sulfonamides in porcine muscle. Results for 40 samples were available in just over 5 h after the completion of a simple sample preparation protocol. Twenty sulfonamide compounds were detected. Acetylated metabolites were not recognised by the binding protein. Limit of detection (mean–three times standard deviation value when n = 20) was calculated to be 16.9 ng g−1 in tissue samples. Intra-assay precision (n = 10) was calculated at 4.3 %CV for a sample spiked at 50 ng g−1 with sulfamethazine, 3.6 %CV for a sample spiked at 100 ng g−1 with sulfamethazine, 7.2 %CV for a sample spiked at 50 ng g−1 with sulfadiazine and 3.1 %CV for a sample spiked at 100 ng g−1 with sulfadiazine. Inter-assay precision (n = 3) was calculated at 9.7 %CV for a sample spiked at 50 ng g−1 with sulfamethazine, 3.8 %CV for a sample spiked at 100 ng g−1 with sulfamethazine, 3.5 %CV for a sample spiked at 50 ng g−1 with sulfadiazine and 2.8 %CV for a sample spiked at 100 ng g−1 with sulfadiazine.
Article
Group-selective molecularly imprinted polymers (MIPs) made from sulfonamides (SAs) using functional monomer methacrylic acid (MAA) were synthesized. The derived molecularly imprinted solid-phase extraction (MISPE) cartridges were developed for the purification and enrichment of aquatic products. The optimum template molecule and the ratio of the functional monomer to the template for obtaining group selectivity to SAs were sulfadimethoxine (SDM) and 4:1, respectively. The MIPs were characterized by Brunauer-Emmett-Teller (BET), scatchard plot, and chromatography analysis, all of which demonstrate better chromatographic behavior and group-selectivity of MIPs for SAs compared with those of corresponding NIPs. The extraction conditions of MISPE for six SAs were optimized; the method precision and accuracy were satisfactory for the fish and shrimp samples at 0.05, 0.1, and 0.2 mg kg(-1) spiked levels. Recoveries ranging from 85.5% to 106.1% (RSD, 1.2-7.0%, n=3) were achieved. The limits of detection (S/N=3) and quantitation (S/N=10) in the shrimp and fish samples were achieved from 8.4 to 10.9 μg kg(-1) and from 22.4 to 27.7 μg kg(-1), respectively. Therefore, the obtained MIPs and MISPE can be employed for the enrichment and clean-up of SAs. This paper presents a new analytical method which enables the simultaneous determination and quantification of SAs in aquaculture products.
Article
A new, rapid, sensitive and selective HPLC method with fluorescence detection is described for the simultaneous determination of 12 sulfonamides, in the presence of putrescine as internal standard, after pre-column derivatization with fluorescamine. The drugs were separated on a Chromolith Performance RP-18 column (100x4.6 mm), using a gradient elution with a binary mobile phase of methanol/0.05 M acetate buffer (pH 3.4). Linearity of derivatization was obtained for concentrations from 3.0 to 300 microg/L in standard solutions. The whole procedure was evaluated and fully validated, according to the European Union Decision 2002/657/EC, for the determination of sulfonamides in turkey muscle and hen eggs following SPE. The LODs varied from 2 to 17 microg/kg in turkey and 2 to 15 microg/kg in egg samples. The average recoveries ranged between 96.9-108.6% in turkey muscle and 96.0-108.4% in egg samples, respectively.
Article
A novel method for the simultaneous analysis at trace level of sulfonamides (sulfaguanidine, sulfanilamide, sulfacetamide, sulfathiazole, sulfapyridine, sulfachloropyridazine, sulfamerazine, sulfameter, sulfamethazine, sulfadoxine, sulfadiazine, sulfamonomethoxine, sulfadimethoxine) in honey is described. Methanol has been used in the sample treatment step to avoid the emulsion formation and to break the N-glycosidic bond between sugars and sulfonamides. The determination is carried out by liquid chromatography in gradient elution mode, with fluorescence detection after the on-line pre-column derivatization with fluorescamine. The influence of parameters such as the mobile phase composition, column temperature, pH or injection volume, on the separation has been taken into account and the derivatization step has also been optimized. Recoveries of the compounds on spiked honey samples ranged from 56% for sulfadoxine to 96% for sulfacetamide, with relative standard deviations below 10%. The quantitation limits are between 4 and 15 ng g(-1).
Molecularly imprinted polymers have been applied as selective sorbents in several analytical techniques, including liquid chromatography, capillary electrophoresis and capillary electrochromatography, solid-phase extraction, and 'immunoassay'. An advantage of this type of sorbent is the possibility to synthesize polymers with selectivity pre-determined for a particular analyte. This review critically discusses the use of imprinted polymers for analysis of drugs and other compounds in biological samples, with emphasis on their use as highly selective solid-phase extraction sorbents for sample pre-concentration and alternative binding entities in immunoassay type protocols.
Article
Development of antibodies with broad specificity recognition for sulfonamide drugs was found to be surprisingly difficult when conventional immunochemical strategies were applied to hapten design. To improve the cross-reactivity pattern of antibodies for the family of sulfonamide drugs, a novel strategy based on the single-ring (fragment-derived) hapten moieties with different spacer substituent lengths was employed for the preparation of immunogens, coating conjugates, and enzyme competitors. The rabbit antibodies raised against a common (one-ring) p-aminobenzenesulfonamide hapten moiety (attached to a carrier protein through the N-1 position) in combination with a homologous hapten-peroxidase tracer allowed the detection of 15 sulfonamide species at the maximum residue limit level using direct ELISA. The two-ring 6-(4-aminobenzensulfonylamino)hexanoic hapten mimics, previously reported in the literature as a weak generic antigen, generated surprisingly superior immune responses in rabbits. The antibodies raised against this two-ring hapten were capable of detecting at least 19 and 17 sulfonamides in a direct ELISA system at the regulatory level with sensitivities corresponding to 20 and 50% binding inhibition, respectively. A negligible cross-reaction with N4 metabolites makes it possible to measure responses of parent sulfonamides in the presence of their metabolized forms. In skimmed milk, the highest limit of detection (LOD) for sulfacetamide defined as 20% inhibition was 65.2 microg x L(-1) (IC20 value), whereas the additional 18 sulfonamides tested exhibited LODs in the range of 0.2-36.8 microg x L(-1). This sensitivity allows simple multisulfonamide tests to be established for use in the laboratory or on site.
Article
A new analytical method, based on capillary electrophoresis and tandem mass spectrometry (CE-MS2), is proposed and validated for the identification and simultaneous quantification of 12 sulfonamides (SAs) in pork meat. The studied SAs include sulfathiazole, sulfadiazine, sulfamethoxypyridazine, sulfaguanidine, sulfanilamide, sulfadimethoxyne, sulfapyridine, sulfachloropyridazine, sulfisoxazole, sulfasalazine, sulfabenzamide and sulfadimidine. Different parameters (i.e. separation buffer, sheath liquid, electrospray conditions) were optimized to obtain an adequate CE separation and high MS sensitivity. MS2 experiments using an ion trap as analyzer, operating in the selected reaction monitoring (SRM) mode, were carried out to achieve the required number of identification points according to the 2002/657/EC European Decision. For the quantification in pork tissue samples, a pressurized liquid extraction (PLE) procedure, using hot water as extractant followed by an Oasis HLB cleanup, was developed. Linearity (r between 0.996 and 0.997), precision (RSD<14 %) and recoveries (from 76 to 98%) were satisfactory. The limits of detection and quantification (below 12.5 and 46.5 microg kg(-1), respectively) were in all cases lower than the maximum residue limits (MRLs), indicating the potential of CE-MS2 for the analysis of SAs, in the food quality and safety control areas.
Article
A multi-screening approach for monitoring potential chemical contaminants in honey by liquid chromatography-electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS) has been developed. A total of 42 veterinary drugs (5 tetracyclines, 7 macrolides, 3 aminoglycosides, 8 beta-lactams, 2 amphenicols and 17 sulfonamides) were surveyed with the ultimate goal of unambiguously confirmed and quantified these analytes at a concentration level of 20 microg/kg. A basic sample preparation including four subsequent liquid/liquid extraction steps was necessary to adequately extract the compounds of interest from the honey. The four extracts were injected into the LC-ESI-MS/MS using a stacking injection procedure. Validation of the entire procedure was carried out according to the European Union directive 2002/657/EC at three concentration levels, i.e., 10, 20 and 30 microg/kg. Good performance data were obtained for 37 analytes, out of the 42 studied. Limit of compliance and detection limit were calculated based on an internal limit set at 20 microg/kg for all the compounds and ranged between 24-30 and 27-80 microg/kg, respectively. A limited survey on honeys of different geographical origins has demonstrated that positive honey samples were often contaminated by more than one class of drugs, thus highlighting the usefulness of such multi-screening approach to ensure and warrants the quality of honey.
Article
A selective imprinted amino-functionalized silica gel sorbent was prepared by combining a surface molecular imprinting technique with a sol-gel process for online solid-phase extraction-HPLC determination of three trace sulfonamides in pork and chicken muscle. The imprinted functionalized silica gel sorbent exhibited selectivity and fast kinetics for the adsorption and desorption of sulfonamides. With a sample loading flow rate of 4 mL min (-1) for 12.5 min, enhancement factors and detection limits for three sulfonamides ( S/ N = 3) were achieved. The precision (RSD) for nine replicate online sorbent extractions of 5 microg L (-1) sulfonamides was less than 4.5%. The sorbent also offered good linearity ( r (2) > 0.99) for online solid-phase extraction of trace levels of sulfonamides. The method was applied to the determination of sulfonamides in pork and chicken muscle samples. The prepared polymer sorbent shows promise for online solid-phase extraction for HPLC determination of trace levels of sulfonamides in pork and chicken samples.
Article
Food contamination continues to be a serious problem around the world. Surveillance of chemical contaminants in foods is important not only for public health but also because of the negative economic impact of contamination. From the analytical perspective, analysis of contaminants in food is an extremely challenging area. There is a wide variety of questions, ranging from the quantification of extremely low levels of individual components to the detailed assessment and evaluation of the analytical technique possibilities. This review considers the applications of CE coupled to MS detection (CE-MS) for the analysis of organic contaminants in food. Analytical information on sample concentration techniques, as well as on the CE separation conditions and recoveries obtained from water and food are provided. Different sections include several fields of application, such as pesticides, drug residues, or toxic formed during food processing in different matrices. A number of tables report a comprehensive listing of CE-MS applications. As a result, this work presents an update overview on the principal application of CE-MS together with a discussion of their main advantages and drawbacks, and an outline of future trends on analysis of organic contaminants.