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Abstract

The present study aimed to evaluate the Strata-X® sorbent, commonly used in cartridges, through analysis by high-performance liquid chromatography coupled with mass spectrometry. Due to the different physical-chemical characteristics of the compounds, different conditions of chromatography and mass analysis were necessary. The developed methods were validated in terms of selectivity, linear range, linearity (coefficient of determination, r²), the limit of detection (LOD), the limit of quantification (LOQ), accuracy (recovery, %), and precision (RSD, %). The results allowed us to select efficient extraction methods, using methanol acidified to pH 2 with formic acid, to elute the herbicides 2,4-D and dicamba in both sorbent materials. Besides, the Strata-X® sorbent was efficient in the sorption of analytes; thus, we indicate it for potential use in air sampling as an alternative to XAD-2.

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... 2,4-D (2,4-dichlorophenoxyacetic acid) is another effective phenoxy herbicide for broadleaf weed control that has been widely used since the 1940s [5][6][7]. However, both herbicides carry a high risk of off-target movement and can cause damage to non-resistant plants at extremely low dosages [8][9][10][11]. Dicamba drift in particular has become a national problem [12,13]. During the first year of dicamba applications on dicamba-resistant soybeans, damage to non-target soybeans that were sensitive to dicamba impacted an estimated 3.6 million acres [14]. ...
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In soybeans, off-target damage from the use of dicamba and 2,4-D herbicides for broadleaf weed control can significantly impact sensitive vegetation and crops. The early detection and assessment of such damage are critical for plant diagnostic labs and regulatory agencies to inform regulated usage policies. However, the existing technologies that calculate the average spectrum often struggle to detect and differentiate the damage caused by these herbicides, as they share a similar mode-of-action. In this study, a high-precision spatial and spectral imaging solution was tested for the early detection of dicamba and 2,4-D-induced damage in soybeans. A 2021 study was conducted using LeafSpec, a touch-based hyperspectral leaf scanner, to detect damage on soybean leaves. VIS-NIR (visible–near infrared) hyperspectral images were captured from 180 soybean plants exposed to nine different herbicide treatments at different intervals after spraying. Leaf damage was distinguished as early as 2 h after treatment (HAT) using pairwise partial least squares discriminant analysis (PLS-DA) models based on spectral data. Leaf color distribution, texture, and morphological features were analyzed to separate herbicide dosages. By fully exploiting the spatial and spectral information from high-resolution hyperspectral images, classification accuracy was improved from 57.4% to over 80% for all evaluation dates. This work demonstrates the potential and advantages of using spectral and spatial features of LeafSpec hyperspectral images for the early and accurate detection of herbicide damage in soybean plants.
... These herbicides mimic natural auxin at the hormonal level selectively in dicotyledonous weeds, causing abnormal growth, senescence and plant death (Groosman, 2010). Both dicamba and 2,4-D have physicochemical properties that are prone to volatilize and cause damage to sensitive crops of adjacent fields Mortensen, 2014, Riter et al. 2021) such as cucumber, cantaloupe and citrus, even at extremely low doses (Ceolin et al. 2021;Hand et al. 2020). Citrus cultivation has considerable economic and social importance in Brazil, and at present, the country is responsible for 13% of world production, ranking second only behind China, which represents 27% of this production (FAO, 2021). ...
Article
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The auxinic herbicides 2,4-D and dicamba are very prone to volatilization and can be carried by wind hundreds of meters to non-target environments. Effects of auxinic herbicide drift on susceptible broadleaf crops from adjacent fields are well documented; however, such effects on the soil microbiota and/or weeds also from adjacent fields have rarely been studied. In this research, the impact of simulated drift of 2,4-D and dicamba subdoses (0D, 1/256D, 1/64D, 1/4D, 1/16D and 1D) were evaluated on ‘ponkan’ mandarin (Citrus reticulata Blanco) seedlings, mandarin rhizosphere microbiota and Amaranthus retroflexus. The full field dose (1D) of dicamba and 2,4-D was 720 and 2345 g ae ha−1, respectively. Dicamba promoted 15 and 18% more foliar abscission and chlorophyll degradation than 2,4-D at 28 days after treatment (DAA). Dicamba also reduced the photosynthesis rate by 60% compared to the control at 28 DAA. Both herbicides at 1D increased intercellular carbon concentration by 15-20%, while reducing transpiration rates by up to 70-90% at 28 DAA. However, no herbicide affected chlorophyll fluorescence in mandarin seedlings. Regarding the soil microbiota, dicamba at 1/16D increased the soil respiration rate by 37% compared to the control. In contrast, 2,4-D produced a greater increase in C-CO2 than dicamba at 1D. Both herbicides at 1D reduced carbon in microbial biomass by 75 and 80%. Doses of 1/4D or more of both herbicides were able to control and reduce the dry matter of A. retroflexus by ≤80% at 21 DAA. Drift of dicamba was more toxic than 2,4-D for mandarin seedlings; however, both herbicides affected several physiological processes of the plants. Furthermore, dicamba and 2,4-D also caused alterations in the soil microbiota and weeds of adjacent fields.
Article
Herbicides play a crucial role in sustaining crop productivity. However, growing concerns about their impact on both the environment and human health necessitate strategies to improve their effectiveness and suitability. Of particular concern are volatile herbicides like 2,4-dichlorophenoxyacetic acid (2,4-D), which not only pose risks to the environment but also impact neighboring crops. To deal with this, we developed a microparticle system comprising chitosan ionotropically crosslinked with tripolyphosphate anions to encapsulate 2,4-D. Optimization of the biopolymer/herbicide ratio yielded remarkable encapsulation efficiencies (> 95%) and loading capacities (> 32%). Characterization analyses revealed interactions between 2,4-D and chitosan, resulting in microparticles (1.7 ± 0.4 µm) with distinct thermal, morphological, and surface charge properties compared to pristine microparticles. In vitro experiments demonstrated pH-dependent release kinetics, with optimal release observed under neutral conditions. A 94% release was achieved at pH 7 after 37 days, driven by sustainable diffusional processes. This ability to control the release of 2,4-D was pivotal in controlling its volatilization. As demonstrated, the volatilization rate for 2,4-D encapsulated within the chitosan microparticles was found to be 64 times lower compared to the commercial herbicide. This encapsulation approach presents an innovative strategy for regulating the presence of 2,4-D in agricultural settings, effectively tackling its significant volatility concerns.
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A large number of agronomic and horticultural crops are susceptible to injury and yield loss from drift-level exposures to synthetic auxin herbicides. A new generation of genetically modified crops including cotton ( Gossypium hirsutum ), field corn ( Zea mays ), soybean ( Glycine max ), and canola ( Brassica napus ) with resistance to dicamba and 2,4-D herbicides has been developed to address the problem of glyphosate-resistant weeds. In the few years since their commercial introduction, these technologies have been rapidly adopted. The objective of this study was to determine the potential effects of simulated, single drift events of 2,4-D and dicamba on pecan ( Carya illinoinensis ) trees. 2,4-D amine [3.8 lb/gal acid equivalent (a.e.)] or dicamba-Diglycolamine salt (4.0 lb/gal a.e.) were applied in 1.0%, 0.1%, and 0.01% by volume spray solutions to pecan trees in June 2013. In 2016 and 2017, 2,4-D choline (3.8 lb/gal a.e.) or dicamba-N,N-Bis-(3-aminopropyl) methylamine (5.0 lb/gal a.e.) were applied in 1.0%, 0.1%, and 0.01% by volume spray solutions to pecan trees in May. These results suggest that serious injury can occur to pecan trees receiving a drift application of 1.0% by volume dicamba or 2,4-D. This injury includes deformed foliage, dead foliage, dead limbs, and/or branches, and arrested nut development. There were no major differences in the response of pecan to either dicamba or 2,4-D at similar rates in this study. Pecan damage resulting from off-target movement of 2,4-D and dicamba at rates ≥1% by volume has the potential to cause significant injury. Yield was not negatively affected by any of the treatments, suggesting that pecan trees can compensate for the observed injury to some extent. The effect of treatments on percent kernel was variable.
Article
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Herbicide active ingredients, formulation type, ambient temperature, and humidity can influence volatility. A method was developed using volatility chambers to compare relative volatility of different synthetic auxin herbicide formulations in controlled environments. 2,4-D or dicamba acid vapors emanating after application were captured in air-sampling tubes at 24, 48, 72, and 96 h after herbicide application. The 2,4-D or dicamba was extracted from sample tubes and quantified using liquid chromatography and tandem mass spectrometry. Volatility from 2,4-D dimethylamine (DMA) was determined to be greater than that of 2,4-D choline in chambers where temperatures were held at 30 or 40 C and relative humidity (RH) was 20% or 50%. Air concentration of 2,4-D DMA was 0.399 µg m ⁻³ at 40 C and 20% RH compared with 0.005 µg m ⁻³ for 2,4-D choline at the same temperature and humidity at 24 h after application. Volatility from 2,4-D DMA and 2,4-D choline increased as temperature increased from 30 to 40 C. However, volatility from 2,4-D choline was lower than observed from 2,4-D DMA. Volatility from 2,4-D choline at 40 C increased from 0.00458 to 0.0263 µg m ⁻³ and from 0.00341 to 0.025 µg m ⁻³ when humidity increased from 20% to 50% at 72 and 96 h after treatment, respectively, whereas, volatility from 2,4-D DMA tended to be higher at 20% RH compared with 50% RH. Air concentration of dicamba diglycolamine was similar at all time points when measured at 40 C and 20% RH. By 96 h after treatment, there was a trend for lower air concentration of dicamba compared with earlier timings. This method using volatility chambers provided good repeatability with low variability across replications, experiments, and herbicides.
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Agarose gel-based passive samplers are nowadays one of the most effective sampling devices able to provide a quantitative evaluation of water contamination level for a broad range of organic contaminants. These devices show significant improvements in comparison to the previous passive samplers dedicated to hydrophilic compounds because they tend to reduce the effect of hydrodynamic flow conditions on the uptake rate of compounds and thus subsequently to improve their accuracy. However, albeit their effects minimized, hydrodynamic water flow and temperature are reported as variables likely to change the uptake rate of compounds that may lead to some inaccuracy if they are not adequately taken into account. This work aims to investigate the magnitude of effects of such uncorrected variables on the bias of the deduced water contamination level. The analysis of the error structure shows that the uncertainty on the diffusivity of contaminants in agarose gel and its dependency on temperature are the most inferring factors. At 8 °C, these factors are, respectively, responsible of 34 and 33% of the squared uncertainty on the final deduced contamination level. The overall uncertainty for a single exposed passive sampler is in the order of 39% and drops to 23% if threesamplers are co-exposed (at 8 °C). Despite this uncertainty, we present results for a set of pesticides and personal care products throughout a field monitoring conducted over a 4-month period, which show the potential of passive samplers to allow assessing the temporal trend of water contamination.
Presentation
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Invited lecture at the 6th Latin America Pesticide Residue Workshop ”LAPRW 2017”
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Volatilization plays an important role in the process of herbicide dispersion in the environment. The physicochemical characteristics of the clomazone molecule indicate its volatility potential. The present study aimed to evaluate the volatilization rate of three clomazone formulations under field conditions using indicator plants and wind tunnels. Transparent polyethylene tunnels were placed on a sorghum (Sorghum bicolor) field parallel to the prevalent wind direction, and the herbicide formulations were applied in plastic trays containing 10 kg of sieved soil and placed at the center of the tunnel. The experiment was arranged in a slip-plot design with four replications. The main plots were represented by different formulations of the herbicides: Gamit 360 CS®, Gamit 500 EC® and Gamit Star®, and control plots without herbicide application. The sub-plots represented the distances from the application site: 1, 2, 3, 4, 5, 6 meters. Herbicide injury in sorghum was then assessed at different days after application. The symptoms of all formulations were more intense in the plants that were closer to the application site, and were even more severe in the prevailing wind direction. In general, regardless of the application distance, Gamit 360 CS® caused less injury to the sorghum. It is concluded that among the formulations assessed, Gamit 360 CS® has a lower volatilization rate and, consequently, lower contamination risk of neighboring crops and the environment. The other two formulations have higher volatility potential.
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Greenhouse experiments were conducted at Wooster, OH, during 2010 and 2011 growing seasons to evaluate the responses of five wine grape cultivars to sublethal doses of 2,4-D, dicamba, and glyphosate, and the 'Riesling' grape to mixtures of 2,4-D plus glyphosate and dicamba plus glyphosate. Treatments were made using a spray system calibrated to deliver 0.757 L min⁻¹ at 276 kPa and 4.8 km h⁻¹. Herbicides were delivered through 8002 flat spray nozzles and applied at 1/30, 1/100, and 1/300 of the recommended field rate of 840, 560, and 840 g ae ha⁻¹ for 2,4-D, dicamba, and glyphosate, respectively. Injury was observed in all treatments 7 d after treatment (DAT). However, injury symptoms greater than 10% were observed 42 DAT in plants treated with 2,4-D at all rates and plants treated with dicamba at the two highest rates. Injury (35%) at 357 DAT was noted only in plants treated with the highest rate of 2,4-D. French hybrids showed slightly less injury symptoms compared with wine grapes at 7 and 42 DAT. Shoot length reduction in plants treated with 2,4-D at the highest rate was 43, 84, and 16% at 7, 42, and 357 DAT, respectively. Glyphosate caused the fewest injury symptoms in Riesling compared with 2,4-D and dicamba when applied separately or tank mixed with glyphosate. Shoot length reduction in Riesling was observed 42 DAT with all rates of 2,4-D, with and without glyphosate and dicamba, and dicamba plus glyphosate at the highest rate; however, at 357 DAT, no effect was observed in shoot length. Spray drift of 2,4-D and dicamba can severely injure grapes, with injury increasing with increased exposure. The combination of 2,4-D plus glyphosate caused greater injury and shoot length reduction in grapes than glyphosate applied alone. Nomenclature: 2,4-D; dicamba; glyphosate; wine grape, Vitis vinifera L. 'Riesling', 'Chardonnay', 'Chardonel', 'Traminette', 'Vidal blanc'.
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A reliable multiresidue method for determination of pesticide and antibiotic residues based on solid-phase extraction (SPE) was developed for the determination of 87 compounds in surface water by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Parameters that might influence the extraction efficiency such as sample loading volume, flow rate and eluent volume were optimized. The experimental results showed excellent linearity for the most of compounds (r2 > 0.99) over the range of 1.0 to 250.0 μg L-1. Most of the analyzed compounds showed limits of detection (LOD) and quantification (LOQ) between 0.01 and 0.04 μg L-1, respectively. Recoveries achieved with spiked water samples were in the range of 70.0 to 120.0% for 86.2% of the analyzed compounds in the three fortification levels (1.0, 2.5, 5.0 μg L-1), with good precision. The multiresidue method developed could be used to determine multiclasses of pesticides and antibiotics simultaneously in superficial water samples with less cost, shorter analytical time and less solvent consumption.
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Herbicides are powerful chemical agents that exert strong biological activity on plants. The release of new formulations of dicamba and 2,4-D and their use in transgenic agronomic crops will probably result in many more applications during the time of year when sensitive nontarget vegetation will be present. The use of herbicides is regulated by the U.S. Environmental Protection Agency, and there are usually no negative effects on nontarget species. One negative aspect of herbicide use occurs when the application moves away from the target area and causes unwanted plant injury on susceptible species. Interest in herbicide drift is increasing, as evidenced by the number of refereed articles that investigate the mitigation or potential for herbicide drift (Figure 1). Although the topic of herbicide drift is broad, in this manuscript I will focus on an overview of off-site movement from a historical perspective and then discuss specific research protocols to examine vapor drift.
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A simple, rapid, and efficient sample pretreatment technique, based on solvent-based de-emulsification dispersive liquid-liquid microextraction (SD-DLLME), followed by high performance liquid chromatography (HPLC) has been developed for simultaneous preconcentration and trace detection of 2,4-dichlorophenoxyacetic acid (2,4-D) and 2-methyl-4-chlorophenoxyacetic acid (MCPA) in water and urine samples. Some parameters such as acidity of solution, the amount of salt, type, and volume of extraction solvents, type of disperser/de-emulsifier solvent, and its volume were investigated and optimized. Under optimum extraction conditions, the limits of detections (LODs) of this method for MCPA and 2,4-D were 0.2 and 0.6 μg L(-1) (based on 3Sb/m) in water and 0.4 and 1.6 μg L(-1) in urine, respectively. Furthermore, dynamic linear range of this method for MCPA and 2,4-D was 1-300 and 2-400 μg L(-1), repectively. Finally, the applicability of the proposed method was evaluated by extraction and determination of the herbicides in urine and different water samples.
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Chromatography combined with several different detection systems is one of the more used and better performing analytical tools. Chromatography with tandem mass spectrometric detection gives highly selective and sensitive analyses and permits obtaining structural information about the analites and about their molar masses. Due to these characteristics, this analytical technique is very efficient when used to detect substances at trace levels in complex matrices. In this paper we review instrumental and technical aspects of chromatography-tandem mass spectrometry and the state of the art of the technique as it is applied to analysis of toxic substances in food.
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An ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) method for determination of 34 mycotoxins in dietary supplements containing green coffee bean (GCB) extracts was developed, evaluated and used in analysis of 50 commercial products. A QuEChERS-like procedure was used for isolation of target analytes from the examined matrices. Average recoveries of the analytes were in the range of 75-110%. The precision of the method expressed as relative standard deviation was below 12%. Limits of detection (LODs) and limits of quantitation (LOQs) ranged from 1.0 to 50.0 µg/kg and from 2.5 to 100 µg/kg, respectively. Due to matrix effects, the method of standard additions was used to ensure accurate quantitation. Ochratoxin A, ochratoxin B, fumonisin B1 and mycophenolic acid were found in 36%, 32%, 10%, and 16% of tested products, respectively. Mycotoxins occurred in the following concentration ranges: ochratoxin A: 2.7-136.9 µg/kg, ochratoxin B: 3.5-20.2 µg/kg, fumonisin B1: 110.0-415.0 µg/kg, mycophenolic acid: 43.1-395.0 µg/kg. High resolution mass spectrometry operated in full MS and MS/MS mode was used to confirm the identities of the reported compounds.
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Volatilization may represent a major dissipation pathway for pesticides applied to soils or crops, accounting for up to 90% of the application dose in some cases. This paper collects and discusses recent data in the literature about this process. On the day of application, pesticide volatilization rates ranged from 0.1 g·ha-1·h-1 for prometton compound to 80 g·ha-1·h-1 for fonofos, for example. In general, pesticides are volatilized from plant surfaces to a greater extent and faster than from the soil. Volatilization continues for from a few days to several weeks (or sometimes even more), occasionally displaying a diurnal cycle. According to the experimental studies reported in the literature, the main factors affecting this process during the first few days after treatment have been identified as follows: the physico-chemical characteristics of the compound and the environmental conditions (temperature, soil moisture, nature of the soil or the crop) are key parameters, along with management practices.
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We collected indoor air, surface wipes (floors, table tops, and window sills), and floor dust samples at multiple locations within 11 occupied and two unoccupied homes both before and after lawn application of the herbicide 2,4-D. We measured residues 1 week before and after application. We used collected samples to determine transport routes of 2,4-D from the lawn into the homes, its subsequent distribution between the indoor surfaces, and air concentration as a function of airborne particle size. We used residue measurements to estimate potential exposures within these homes. After lawn application, 2,4-D was detected in indoor air and on all surfaces throughout all homes. Track-in by an active dog and by the homeowner applicator were the most significant factors for intrusion. Resuspension of floor dust was the major source of 2,4-D in indoor air, with highest levels of 2,4-D found in the particle size range of 2.5-10 microm. Resuspended floor dust was also a major source of 2,4-D on tables and window sills. Estimated postapplication indoor exposure levels for young children from nondietary ingestion may be 1-10 microg/day from contact with floors, and 0.2-30 microg/day from contact with table tops. These are estimated to be about 10 times higher than the preapplication exposures. By comparison, dietary ingestion of 2,4-D is approximately 1.3 microg/day.
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This study presents concurrently sampled ambient air data for a range of persistent organic pollutants at the continental scale. This was achieved using a passive air sampling system, deploying polyurethane foam disks, which was prepared in one laboratory, sealed to prevent contamination, sent out by courier to volunteers participating in different countries, exposed for 6 weeks, collected, resealed, and returned to the laboratory for analysis. Europe was the study area--a region with a history of extensive POPs usage and emission and with marked national differences in population density, the degree of urbanization and industrial/agricultural development. Samplers were deployed at remote/rural/urban locations in 22 countries and analyzed for PCBs, a range of organochlorine pesticides (HCB, alpha-HCH, gamma-HCH, ppDDT, ppDDE), and PBDEs. Calculated air concentrations were in line with those obtained by conventional active air sampling techniques. The geographical pattern of all compounds reflected suspected regional emission patterns and highlighted localized hotspots. PCB and PBDE levels varied by over 2 orders of magnitude; the highest values were detected in areas of high usage and were linked to urbanized areas. HCB was relatively uniformly distributed, reflecting its persistence and high degree of mixing in air. Higher gamma-HCH, ppDDT, and ppDDE levels generally occurred in South and East Europe.
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Anyone clicking on this link before September 27, 2019 will be taken directly to the final version of your article on ScienceDirect, which they are welcome to read or download. No sign up, registration or fees are required: https://authors.elsevier.com/c/1ZXEIzLNSODMD New Zealand uses more than a ton of pesticides each year; many of these are mobile, relatively persistent, and can make their way into waterways. While considerable effort goes into monitoring nutrients in agricultural streams and programs exist to monitor pesticides in groundwater, very little is known about pesticide detection frequencies, concentrations, or their potential impacts in New Zealand streams. We used the ‘Polar Organic Chemical Integrative Sampler’ (POCIS) approach and grab water sampling to survey pesticide concentrations in 36 agricultural streams in Waikato, Canterbury, Otago and Southland during a period of stable stream flows in Austral summer 2017/18. We employed a new approach for calculating site-specific POCIS sampling rates. We also tested two novel passive samplers designed to reduce the effects of hydrodynamic conditions on sampling rates: the ‘Organic-Diffusive Gradients in Thin Films’ (o-DGT) aquatic passive sampler and microporous polyethylene tubes (MPTs) filled with Strata-X sorbent. Multiple pesticides were found at most sites; two or more were detected at 78% of sites, three or more at 69% of sites, and four or more at 39% of sites. Chlorpyrifos concentrations were the highest, with a maximum concentration of 180 ng/L. Concentrations of the other pesticides were generally below 20 ng/L. Mean concentrations of individual pesticides were not correlated with in- stream nutrient concentrations. The majority of pesticides were detected most frequently in POCIS, presumably due to its higher sampling rate and the relatively low concentrations of these pesticides. In contrast, chlorpyrifos was most frequently detected in grab samples. Chlorpyrifos concentrations at two sites were above the 21-day chronic ‘No Observable Effect Concentration’ (NOEC) values for fish and another two sites had concentrations greater than 50% of the NOEC. Otherwise, concentrations were well-below NOEC values, but close to the New Zealand Environmental Exposure Limits in several cases.
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Phosphorylated compounds and organic acids with multiple carboxylate groups are commonly observed to have poor peak shapes and signal in LC/MS experiments. The poor peak shape is caused by the presence of trace metals, particularly iron, contributed from a variety of sources within the chromatographic system. To ameliorate this problem, different solvent additives were investigated to reduce the amount of metal in the flow path to achieve better analytical performance for these metal-sensitive compounds. Here, we introduce the use of a solvent additive that can significantly improve the peak shapes and signal of metal-sensitive metabolites for LC/MS analysis. Moreover, the additive is shown to be amenable for other metal-sensitive applications, such as the analysis of phosphopeptides and polar phosphorylated pesticides, where the instruments could be used in either positive or negative analysis mode.
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Lycium ruthenicum Murray (LR) is a functional food, and it has long been used in traditional folk medicine. However, detailed qualitative and quantitative analyses related to its phenolic compounds remains scarce. This work reports, for the first time, the establishment of a rapid method for simultaneous identification and quantification of 25 phenolic compounds by UPLC-quadrupole-Orbitrap mass spectrometry (UPLC-Q-Orbitrap MS). This method was validated by LODs, LOQs, precision, repeatability, stability, mean recovery, recovery range and RSD. The confirmed method was applied to the analysis of phenolic compounds in LR. Finally, 18 phenolic compounds in LR were qualitatively and quantitatively analyzed. Among them, 11 constituents were detected for the first time, which included two flavonoids (catechin and naringenin) and seven phenolic acids (gallic acid, vanillic acid, 2,4-dihydroxybenzoic acid, veratronic acid, benzoic acid, ellagic acid and salicylic acid). Moreover, Phloretin and protocatechuate, belonging to the dihydrochalcone flavonoid and protocatechuic acid respectively, were also identified and quantified. The total phenolics content (20.17 ± 2.82 mg/g) and the total anthocyanin content (147.43 ± 1.81 mg/g) were determined. In addition, the antioxidant activities of the LR extract were evaluated through 2,2-azinobis (3-ethylbenzthiazoline-6-sulphonic acid) (ABTS) radical scavenging activity, ferric reducing antioxidant power (FRAP) and total antioxidant activity (T-AOC) assays.
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Non-targeted screening methods with ultra-high-performance liquid chromatography-electrospray ionization/quadrupole-time-of-flight mass spectrometry have been extensively applied to plant metabolomics to very diverse scientific issues in plant metabolomics. In this study different mobile phase additives were tested in order to improve electrospray ionization process and to detect as many metabolites as possible with high peak intensities in positive and negative ionization mode. Influences of modifiers were examined for nonpolar and polar compounds, as optimal conditions are not always the same. By combining different additives, metabolite coverage could be significantly increased. Best results for polar metabolites in positive ionization mode were achieved by using 0.1% acetic acid and 0.1% formic acid in negative ionization mode. For measurements of nonpolar metabolites in positive ionization mode, the application of 10 mmol/L ammonium formate led to best findings, while the use of 0.02% acetic acid was more appropriate in negative ionization mode.
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In this study, the efficiency of a new fluorinated sorbent for dispersive solid-phase extraction (d-SPE) clean-up in extracts provided by the QuEChERS (Quick, Easy, Cheap, Effective, Rugged and Safe) acetate method from tomato and sweet pepper samples was evaluated by ultra-high performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS). Clean-up using d-SPE technique has been widely used associated with the QuEChERS method. The most commonly sorbents used in d-SPE are primary secondary amine (PSA), octadecylsilane (C18) and graphitized carbon black (GCB), which are indicated to remove sugars, fatty acids, pigments, among others. The performance of an alternative fluorinated sorbent was compared with PSA and C18 sorbents for representative pesticides and better results were obtained when the fluorinated sorbent was used. Validation presented acceptable results for trueness and precision, with method limit of detection between 0.9 and 1.8 μg kg⁻¹ and limit of quantification from 2.6 to 5.4 μg kg⁻¹. Most of the compounds presented low matrix effect. Results showed that the fluorinated sorbent contribute to the clean-up of the tomato extract and is an effective alternative, with lower costs and greater efficiency. Commercial tomato samples were analyzed using the proposed method and residues of dimethoate, tetraconazole and thiamethoxam were detected.
Chapter
Gradient elution is the method of choice for the separation of samples with a wide retention range. This chapter reviews the basic theory and practical consideration for method development in gradient elution. Optimization requires selection of the range of solvent composition, solvent type, the gradient time, and gradient shape. The linear solvent strength model of gradient elution provides the tools for practical method development and computer-aided optimization of separations starting from a minimum number of trial experiments.
Chapter
Description Get 7 pivotal symposium papers. ASTM International Committee E35 on Pesticides, Antimicrobials, and Alternative Control sponsored this foremost publication on pesticide formulations and delivery systems. Without these selected technical publications, the intercommunication between professionals in the area would be limited. Control of pests is a very important aspect of feeding the world and this series contributes to that effort. Access the most current topics on formulations, adjuvants, and delivery systems. Contributions to this series include industry, government, and academia.
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Bee products can be produced in an environment contaminated by pesticides that can be transported by honey bees to the hive and incorporated into the honey. Therefore, rapid and modern methods to determine pesticide residues in honey samples are essential to guarantee consumers’ health. In this study, a simple multiresidue method for the quantification of 116 pesticides in honey is proposed. It involves the use of a modified QuEChERS procedure followed by UHPLC-MS/MS analysis. The method was validated according to the European Union SANCO/12571/2013 guidelines. Acceptable values were obtained for the following parameters: linearity, limit of detection (0.005 mg/kg) and limit of quantification (0.010 and 0.025 mg/kg), trueness (for the four tested levels the recovery assays values were between 70 and 120%), intermediate precision (RSD<20.0%) and measurement uncertainty tests (<50.0%). The validated method was applied for determination of 100 honey samples from five states of Brazil.
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The development of dicamba-tolerant and other auxin-tolerant crops will enable the use of these effective herbicides in soybean and cotton at application timings such as at planting or over-the-top that are not currently possible. This research examined the effect of various factors on detection of postapplication amounts of dicamba in the air under field conditions by coupling a sample collection system with advanced chemical analysis of those samples. The quantity of dimethylamine salt of dicamba that was detected within 48 hr after application was two times greater (P < 0.05) than the quantity of diglycoamine salt formulation based on field studies in 2009. Regardless of application timing, the amount of detected dicamba was greatest during the 0 to 12 hr time period after application. However, the total detected after 48 hr was less for evening applications (5 micrograms [µg]) compared with midday (17 µg) or morning (14 µg) applications based on 2010 field trials. Average ambient air temperature (and other weather variables) correlated with higher detection levels of dicamba in the air in the field. Nomenclature: Dicamba, soybean, Glycine max (L.) Merr.
Article
With the increase of improper use of pesticides in recent years, monitoring programs for pesticide residues have become commonplace around the world. In Brazil, sweet pepper has presented the highest percentage of irregular samples over 10 years of monitoring. The aim of this study was to optimize and validate a quick and effective method for the determination of 81 pesticides in sweet pepper using modified QuEChERS (quick, easy, cheap, effective, rugged, and safe) method and ultra high-performance liquid chromatography– tandem mass spectrometry (UHPLC-MS/MS). Experimental conditions of sample preparation were optimized by central composite design (CCD) in order to obtain an adequate extraction of the selected compounds. Recoveries from spiked samples at 10, 50, and 100 μg kg−1 ranged between 70 and 120 % with relative standard deviation (RSD) <20 %, except for thiophanate methyl that presented lower recoveries due degradation. Considering the occurrence of matrix effect, the quantification was performed using matrix-matched calibration. The experimental method limits of detection and quantification were 3 or 7.5 and 10 or 25 μg kg−1, respectively. In the analysis of 20 commercial samples of sweet pepper, residues of 14 pesticides were quantified in concentrations ranging from 10 to 294 μg kg−1, some higher than the MRL established by the Brazilian and European legislation. The proposed method combines the advantages of QuEChERS and UHPLC-MS/MS and proved to be suitable for the pesticide multiresidue determination in sweet pepper in routine laboratory analyses.
Article
This paper presents an application of ultra-high performance liquid chromatography electrospray ionization quadrupole Orbitrap high resolution mass spectrometry (UHPLC/ESI Q-Orbitrap MS) for the determination of 451 pesticide residues in fruits and vegetables. Pesticides were extracted from samples using the QuEChERS (quick, easy, cheap, effective, rugged and safe) procedure. UHPLC/ESI Q-Orbitrap MS in full MS scan mode acquired full MS data for quantification, and UHPLC/ESI Q-Orbitrap Full MS/dd-MS2 (i.e. Data Dependent scan mode) obtained product ion spectra for identification. UHPLC/ESI Q-Orbitrap MS quantification was achieved using matrix-matched standard calibration curves along with the use of isotopically labelled standards or a chemical analogue as internal standards to achieve optimal method accuracy. The method performance characteristics include overall recovery, intermediate precision and measurement uncertainty were evaluated according to a nested experimental design. For the ten matrices studied, 94.5% of the pesticides in fruits and 90.7% in vegetables had recoveries between 81% and 110%; 99.3% in fruits and 99.1% in vegetables had an intermediate precision ≤ 20%; and 97.8% in fruits or 96.4% in vegetables showed measurement uncertainty ≤ 50%. Overall, the UHPLC/ESI Q-Orbitrap MS demonstrated acceptable performance for the quantification of pesticide residues in fruits and vegetables. The UHPLC/ESI Q-Orbitrap Full MS/dd-MS2 along with library matching showed great potential for identification and is being investigated further for routine practice.
Article
Growing concern about the environmental impact of ionizable and polar organic chemicals such as pesticides, pharmaceuticals and personal care products has lead to the inclusion of some in legislative and regulatory frameworks. It is expected that future monitoring requirements for these chemicals in aquatic environments will increase, along with the need for low cost monitoring and risk assessment strategies. In this study the uptake of 13 neutral and 6 ionizable pesticides, pharmaceuticals and personal care products by modified POCIS (with Strata™-X sorbent) and Chemcatchers™ (SDB-RPS or SDB-XC) was investigated under controlled conditions at pH = 6.5 for 26 days. The modified POCIS and Chemcatcher™ (SDB-RPS) samplers exhibited similar performance with the uptake of the majority of the 19 chemicals of interest categorised as linear over the 26 day deployment. Only a few ionized herbicides (picloram and dicamba) and triclosan showed negligible accumulation. Chemcatcher™ with SDB-XC sorbent performed relatively poorly with only carbamazepine having a linear accumulation profile, and 8 compounds showing no measurable accumulation. Differences in the uptake behavior of chemicals were not easily explained by their physico-chemical properties, strengthening the requirement for detailed calibration data. PES membranes accumulated significant amount of some compounds (i.e. triclosan and diuron), even after extended deployment (i.e. 26 days). At present there is no way to predict which compounds will demonstrate this behavior. Increasing membrane pore size from 0.2 to 0.45 μm for Chemcatcher™ (SBD-RPS) caused an average increase in Rs of 24%.
Article
Pesticides in the inhalable fraction of particulate matter (PM10) should be well tracked in order to contribute information to future exposure assessment in individuals of the general public. A total of 40 current-used pesticides and metabolites were searched for in ambient air samples collected from January through December 2010. The samples were taken from one remote, one urban and three rural sites in Valencia Region (Spain) and analyzed using liquid chromatography coupled to mass spectrometry in tandem (LC-MS/MS). In the PM10 fraction 17 pesticides and metabolites were detected overall, two of them currently banned (carbofuran and omethoate, although the latter is a metabolite of the permitted pesticide dimethoate). The detected pesticides appeared at frequencies ranging from 1 to 75%, with omethoate, terbuthylazine and its metabolites, and carbendazim presenting the highest frequencies. The concentrations detected ranged from few pg m−3 to thousands of pg m−3, with omethoate having the highest average concentration (141.15 pg m−3) in the 5 sites overall. Each station showed its own specific pesticide profile, which is linked to the different types of crops around each site. In the rural stations pesticide levels were greater in spring and early summer, which correlates with their application in agricultural practices. These findings suggest that more efforts are required to implement an extensive air monitoring network in Europe for pesticide control and to develop regulations or recommendations regarding safer pesticide levels in ambient air.
Article
Six porous copolymers of acrylonitrile (AN)/divinylbenzene (DVB) and methacrylonitrile (MAN)/DVB have been synthesised by suspension polymerization in the presence of inert diluents. They have different specific surface area (460–720 m2/g for AN/DVB and 560–730 m2/g for MAN/DVB) and contain various amounts of the strongly polar nitrile groups. Their sorptive properties have been studied using dilute (0.5 mmol) solutions of phenol and its derivatives (o-chlorophenol, o-, m- and p-nitrophenol, 2,3- and 2,6-dimethylphenol, p-hydroxyphenol). It has been found that sorption of the most hydrophobic compounds and compounds capable of forming strong intramolecular hydrogen bonds does not depend on the polarity of the polymer surface. Sorption of phenol and m- and p-nitrophenol is stronger on sorbents having more polar groups. The influence of these groups on the sorption process is highly significant in the case of hydrophilic, water soluble sorbates such as p-hydroxyphenol. Polymeric sorbents were characterized using elemental analysis, inverse gas chromatography and their porous structure was characterized by nitrogen adsorption at 77 K.
Article
Water is fundamental to the existence of life since it is essential to a series of activities, such as agriculture, power generation, and public and industrial supplies. The residual water generated by these activities is released into the environment, reaches the water systems, and becomes a potential risk to nontarget organisms. This paper reports the development and validation of a quantitative method, based on solid-phase extraction and liquid chromatography tandem mass spectrometry, for the simultaneous analysis of 18 pharmaceuticals and personal care products (PPCPs) and 33 pesticides in surface and drinking waters. The accuracy of the method was determined by calculating the recoveries, which ranged from 70 to 120 % for most pesticides and PPCPs, whereas limits of quantification ranged from 0.8 to 40 ng/L. After the validation step, the method was applied to drinking and surface waters. Pesticides and PPCPs were found in concentrations lower than 135.5 ng/L. The evaluation of different water sources with regard to contamination by pesticides and PPCPs has been quite poor in southern Brazil.
Article
A database has been created for the simultaneous analysis of more than 350 pesticides and veterinary drugs (including antibiotics) using ultra-high performance liquid chromatography coupled to high resolution Orbitrap mass spectrometry (UHPLC-Orbitrap-MS). This is a comprehensive exact mass database built using the Exactive-Orbitrap analyzer. The developed database includes exact masses of the target ions and retention time data, and allows the automatic search of the included compounds. Generic chromatographic and MS conditions have been applied. The presented database is suitable for qualitative analysis, and it was also evaluated for quantitative purposes in routine analysis, after the optimization and validation of a generic extraction method in honey samples. Adequate recovery and precision values for most of the studied analytes were obtained and the limits of detection (LOD) ranged from 1 to 50 μg kg(-1). For pesticides, LODs were always lower than the MRLs established by European Union in honey, except for a few compounds. This method was applied to the analysis of 26 real honey samples and some pesticides (azoxystrobin, coumaphos, dimethoate and thiacloprid) were detected in 4 samples. Azoxystrobin and coumaphos were determined in two different samples (organic honey) at 1.5 μg kg(-1) and 5.1 μg kg(-1). Veterinary drugs were not detected in the analyzed samples.
Article
In this study, directly suspended liquid-phase microextraction was investigated for the extraction and determination of five chlorophenoxy acid herbicides in water samples. The optimized parameters for extraction of chlorophenoxy acid herbicides were 1M HCl concentration in sample solution, solution temperature 20°C, 45-min extraction time, 1,000rpm stirring rate, 25μL extracting solvent volume and without NaCl addition. Under the optimum conditions, the enrichment factor ranged from 192 to 390. Calibration curves yielded good linearity (R 2>0.999) and the linear range was 5.0–500.0μgL−1, limit of detection was 0.3–0.4μgL−1 and limit of quantification was 1–2μgL−1 for analytes and the relative standard deviations were in the range of 3–10% (n=3). Finally, the proposed method was successfully applied to the quantification of five chlorophenoxy acid herbicides in water samples and recovery was in the range of 74–110%. KeywordsColumn Liquid chromatography–DSLPME–Preconcentration–Chlorophenoxy acid herbicides
Article
Developments in the sampling and determination of pesticides in ambient air have been discussed and data on the occurrence of pesticides in atmosphere have been presented. Developments in active sampling methods were reviewed and the different materials used for trapping pesticides from gas and particulate phases were discussed. Likewise, the use and developments of passive air samplers were reviewed. This article pays special attention to the analysis of pesticides trapped from ambient air, and recapitulate the procedures for extraction, clean-up and determination of these substances. Improvements in sampling procedures, analytical methods and monitoring activities are necessary to advance the knowledge of occurrence of currently used pesticides in atmosphere and their impact over environment and humans.
Article
The article reviews the most important methodologies for determining pesticide residues in ambient air. The atmospheric input of pesticides may result from spray drift during application and volatilization after application. Samples are commonly collected from the atmosphere by filters or solid sorbents, keeping in mind that the concentration level of pesticides in the atmosphere can be considerably lower than those in water or soil. Soxhlet extraction and accelerated solvent extraction are the usual means of extracting analytes. The article also covers final determination techniques, the standard ones at present being gas or liquid chromatography coupled with mass spectrometry.
Article
Pharmaceuticals, identified as emerging contaminants, are used in large quantities in human and veterinary medicine for treatment of different diseases. Among pharmaceuticals, antibiotics in the aquatic environment are of great concern as prolonged exposure to low doses may promote antibiotic resistance. The rapid development of liquid chromatography (LC) coupled to mass spectrometry (MS) and tandem MS (MS2) in the environmental field has transformed this combined technique into a valuable tool for the determination of antibiotics in water samples. To be of real value from the environmental and public health point of view, the analysis performed should meet the scientific standards established to assure data quality. These require not only accurate quantitative methods but also reliable confirmative methods, at the low concentration levels expected for antibiotics in water. We present a critical review of published methods based on LC-MS or LC-MS2 for the determination of antibiotic residues in environmental waters. We evaluate different approaches for screening, quantification and confirmation of these compounds, giving special attention to dealing with the intrinsic difficulties of confirming analytes with confidence at low-ng/L levels.
Article
A confirmatory and sensitive procedure has been developed for the determination of 40 currently used pesticides (CUPs) in airborne particulate matter (PM 10) at trace level. The proposed method includes extraction of PM 10-bound pesticides by microwave-assisted extraction (MAE) followed by a gel permeation chromatography (GPC) clean-up and determination by GC-MS/MS. The injection mode and the main parameters in MS/MS were optimized. The matrix effect was also evaluated. Recoveries ranged from 70 to 120% except for pyrimethanil and pirimicarb. The limit of quantification (LOQ) ranged from 1.32 to 39.47 pg m(-3), when air volumes of 760 m(3) were collected. The method was applied to 38 samples collected from a rural station belonging to the atmospheric monitoring network of the Regional Valencia Government (Spain) during April-June 2010. Eighteen out of 40 pesticides investigated were found in at least one sample (bifenthrin, chlorothalonil, chlorpyriphos-e, chlorpyriphos-m, clorpropham, diazinon, dicofol, diphenylamine, fipronil, fludioxonil, folpet, malathion, metalaxyl, penconazole, quinoxyfen, triadimefon, trifluralin, and vinclozoline), with concentrations ranging from 1.32 to 625.80 pg m(-3).
Article
The main objective of the study was to evaluate the applicability of two solid sorbent media (Anasorb 708 and Strata X), the impinger filled with distilled water and PTFE filters for determination of airborne cyclophosphamide (CP) in the hospital working environment. For this purpose, air contamination of Masaryk Memorial Cancer Institute (Czech Republic) was monitored using the sampling apparatus containing the samplers described above. In addition, the surface contamination was also determined using the wipe sampling technique. During the monitoring, contamination of three different workplaces (storage room, preparation room and outpatient clinic) was studied. Using Strata X solid sorbent tubes, airborne CP was determined in all (n = 5) samples collected at the outpatient clinic over a 5 day monitoring period (concentration range: 0.3-4.3 ng m(-3)). Other samplers (including PTFE filters) did not collect any detectable amount of CP (the limit of detection, LOD ≤ 0.1 ng m(-3)). Negative results detected at filter samples indicate that CP determined at Strata X samples was most probably of gaseous origin. Surface contamination ranged from <2 to 19, <8 to 418 and 133-15,500 pg cm(-2) at the storage room, preparation room and outpatient clinic, respectively. The study showed that evaporation of antineoplastic drugs should not be neglected, albeit the concentrations determined in our study are relatively low. Therefore, proper monitoring of airborne contamination should involve simultaneous sampling of both particle-bonded and gaseous phases. In this way, Strata X sorbent tubes seem to be an effective tool for the sampling of gaseous CP in the indoor air.
Article
A method for the simultaneous determination of two biocidal quaternary ammonium compounds; didecyldimethylammonium chloride (didecyldimethyl quat) and dodecylbenzyldimethylammonium chloride (benzyl quat), in seawater by solid phase extraction (SPE) followed by liquid chromatography-mass spectrometry (LC-MS) was developed. The optimised procedure utilised off-line extraction of the analytes from seawater using polymeric (Strata-X) SPE cartridges. Recoveries ranged from 80 to 105%, with detection limits at the low parts-per-trillion (ng/l) level for both analytes. To demonstrate sensitivity, environmental concentrations were measured at three different locations along the North East coast of England with measured values in the range 120-270ng/l.
Article
Passive samplers such as the Polar Organic Chemical Integrative Sampler (POCIS) are useful tools for monitoring trace levels of polar organic chemicals in aquatic environments. The use of performance reference compounds (PRC) spiked into the POCIS adsorbent for in situ calibration may improve the semiquantitative nature of water concentration estimates based on this type of sampler. In this work, deuterium labeled atrazine-desisopropyl (DIA-d5) was chosen as PRC because of its relatively high fugacity from Oasis HLB (the POCIS adsorbent used) and our earlier evidence of its isotropic exchange. In situ calibration of POCIS spiked with DIA-d5 was performed, and the resulting time-weighted average concentration estimates were compared with similar values from an automatic sampler equipped with Oasis HLB cartridges. Before PRC correction, water concentration estimates based on POCIS data sampling rates from a laboratory calibration exposure were systematically lower than the reference concentrations obtained with the automatic sampler. Use of the DIA-d5 PRC data to correct POCIS sampling rates narrowed differences between corresponding values derived from the two methods. Application of PRCs for in situ calibration seems promising for improving POCIS-derived concentration estimates of polar pesticides. However, careful attention must be paid to the minimization of matrix effects when the quantification is performed by HPLC-ESI-MS/MS.
Article
Passive sampling technology has been developing very quickly for the past 20 years, and is widely used for monitoring pollutants in different environments, for example air, water, and soil. It has many significant advantages, including simplicity, low cost, no need for expensive and complicated equipment, no power requirements, unattended operation, and the ability to produce accurate results. The present generation of passive samplers enables detection and analysis of bioavailable pollutants at low and very low concentrations and investigation of the environmental concentration of organic and inorganic pollutants not only on the local scale but also on continental and global scales. This review describes the current application of passive sampling techniques in environmental analysis and monitoring, under both equilibrium and non-equilibrium conditions.
Article
A novel sample preparation method "Dispersive liquid-liquid-liquid microextraction" (DLLLME) was developed in this study. DLLLME was combined with liquid chromatography system to determine chlorophenoxy acid herbicide in aqueous samples. DLLLME is a rapid and environmentally friendly sample pretreatment method. In this study, 25microL of 1,1,2,2-tetrachloroethane was added to the sample solution and the targeted analytes were extracted from the donor phase by manually shaking for 90s. The organic phase was separated from the donor phase by centrifugation and was transferred into an insert. Acceptor phase was added to this insert. The analytes were then back-extracted into the acceptor phase by mixing the organic and acceptor phases by pumping those two solutions with a syringe plunger. After centrifugation, the organic phase was settled and removed with a microsyringe. The acceptor phase was injected into the UPLC system by auto sampler. Fine droplets were formed by shaking and pumping with the syringe plunger in DLLLME. The large interfacial area provided good extraction efficiency and shortened the extraction time needed. Conventional LLLME requires an extraction time of 40-60min; an extraction time of approximately 2min is sufficient with DLLLME. The DLLLME technique shows good linearity (r(2)>or=0.999), good repeatability (RSD: 4.0-12.2% for tap water; 5.7-8.5% for river water) and high sensitivity (LODs: 0.10-0.60microg/L for tap water; 0.11-0.95microg/L for river water).
Article
The use of thin-film polymer-coated glass surfaces or POGs as passive air samplers was investigated during an uptake experiment in an indoor environment with high levels of gas-phase polychlorinated biphenyls (PCBs). POGs consisted of a micron thick layer of ethylene vinyl acetate (EVA) coated onto glass cylinders. The uptake was initially linear with time and governed by the air-side mass transfer coefficient and surface area of the sampler. This was followed by a curvilinear region and finally a constant phase when equilibrium was established between air and EVA. The high surface area-to-volume ratio of the POGs allowed rapid equilibrium with gas-phase PCBs; equilibration times were on the order of hours for the low molecular weight congeners. The equilibrium concentration was dependent on the EVA-air partition coefficient, K(EVA-A), which was shown to be very well correlated to the octanol-air partition coefficient, K(OA). When POGs of varying thickness were equilibrated with air, the amount of PCB accumulated increased with increasing thickness of the EVA, indicating that uptake was by absorption into the entire polymer matrix. A wind field of 4 m s(-1) resulted in an increased uptake rate by a factor of approximately six compared to uptake in relatively still air. This wind speed effect was diminished, however, when POGs were housed in deployment chambers consisting of inverted stainless steel bowls. Relationships based on the air-side mass transfer coefficient and K(EVA-A) were developed for PCBs that describe the entire uptake profile and allow air concentrations to be determined from the amount of chemical accumulated in the POG. It is believed that these relationships are also valid when POGs are used to detect other classes of persistent organic pollutants.
Article
Three types of solid-phase chemical exposure sampling media: cellulose, polyurethane foam, and XAD-2, were analyzed for 2,4-dichlorophenoxyacetic acid (2,4-D) and the amine salts of 2,4-D. Individual samples were extracted into acidified methanol, and the extracts were analyzed via liquid chromatography-tandem mass spectrometry using electrospray ionization and a C(8) reversed-phase LC column. (13)C 2,4-D and a labeled benzoic acid (13)C or d5) were employed as the surrogate and internal standard, respectively. Over a three-year study of pesticide exposure among agricultural workers involving a high volume of analyses, values of average % recovery for (13)C 2,4-D on personal exposure samples ranged from 87 to 98 with a % relative standard deviation ranging from 7 to 12. The performance of the method compares favorably with that of the current National Institute for Occupational Safety and Health-recommended approach for the analysis of 2,4-D on these types of exposure sampling matrices.
Article
Polyurethane foam (PUF) disks were deployed at global background sites, to test logistical issues associated with a global monitoring network for persistent organic pollutants (POPs). alpha-HCH, exhibited relatively high and uniform concentrations (17-150 pg/m3) at temperate and arctic sites with elevated concentrations associated with trans-Pacific inflow. Concentrations were much lower (<5 pg/m3) in Bermuda, Chile and Cape Grim. Concentrations for gamma-HCH, the main component of lindane, were spatially similar to the alpha-HCH pattern but lower in magnitude (typically, <10 pg/m3). Chlordane concentrations (sum of cis-chlordane, trans-chlordane and trans-nonachlor) were also low (<10 pg/m3). Dieldrin concentrations were in the range 2-25 pg/m3 at most sites but elevated in Bermuda. Back trajectories suggest that advection from Africa and the US may contribute. Endosulfan, a popular current-use pesticide, exhibited highest concentrations ranging from tens to hundreds of pg/m3. There was good agreement between duplicate samplers at each site and PUF disk-derived air concentrations agreed with high volume data. Few logistical/analytical problems were encountered in this pilot study.
multirres ıduo Para agrot oxicos e compostos relacionados em ar empregando trapeamento em sorvente polim erico e GC-MS/MS
  • S Martel
  • Etodo
Martel, S. M etodo multirres ıduo Para agrot oxicos e compostos relacionados em ar empregando trapeamento em sorvente polim erico e GC-MS/MS. Ph.D. Dissertation, Universidade Federal de Santa Maria, Santa Maria, RS, 2013.
Determination of Acidic Herbicides in Water Using Liquid Chromatography-Tandem Quadrupole Mass Spectrometry, Waters Corporation
  • R Jandova
  • S Hird
  • E Ross
  • M Van Hulle
Jandova, R.; Hird, S.; Ross, E.; Van Hulle, M. Determination of Acidic Herbicides in Water Using Liquid Chromatography-Tandem Quadrupole Mass Spectrometry, Waters Corporation Jun, 2018. https://www.waters.com/nextgen/in/en/library/application-notes/2018/acidic-herbicides-water-liquid-chromatographytandem-quadrupole-mass-spectrometry.html. (accessed Jan 15, 2020).
Minist erio P ublico recebe documento com preju ızos causados pelo 2,4-D a vinitinicultura ga ucha
  • Instituto Brasileiro
  • Vinho
  • Ibravin
Instituto Brasileiro do Vinho -IBRAVIN. Minist erio P ublico recebe documento com preju ızos causados pelo 2,4-D a vinitinicultura ga ucha. https://www.ibravin.org.br/Noticia/ministeriopublico-recebe-documento-com-prejuizos-causados-pelo-2-4-d-avitivinicultura-gaucha/417. (accessed Jan 15, 2020).
Dinâmica ambiental do herbicida 2,4-D e o potencial de contaminação em plantas de fumo
  • M M Noguera
Noguera, M. M. Dinâmica ambiental do herbicida 2,4-D e o potencial de contaminação em plantas de fumo. Master's Thesis, Universidade Federal de Pelotas, Pelotas, RS, 2017.
de clomazone e ocorrência de agrot oxicos e hormônios ester oides na agua pot avel e da chuva de regiões oriz ıcolas do Sul do Brasil
  • F Schreiber
Schreiber, F. Volatilização de clomazone e ocorrência de agrot oxicos e hormônios ester oides na agua pot avel e da chuva de regiões oriz ıcolas do Sul do Brasil. Ph.D. Dissertation, Universidade Federal de Pelotas, Pelotas, RS, 2012.