Polar Pesticides Research Articles

Soil metabolomics: A powerful tool for predicting and specifying pesticide sorption

Sorption regulates the dispersion of pesticides from cropped areas to surrounding water bodies as well as their persistence. Assessing the risk of water contamination and evaluating the efficiency of mitigation measures, requires fine-resolution sorption data and a good knowledge of its drivers. This study aimed to assess the potential of a new approach combining chemometric and soil metabolomics to estimate the adsorption and desorption coefficients of a range of pesticides. It also aims to identify and characterise key components of soil organic matter (SOM) driving the sorption of these pesticides. We constituted a dataset of 43 soils from Tunisia, France and Guadeloupe (West Indies), covering extensive ranges of texture, organic carbon and pH. We performed untargeted soil metabolomics by liquid chromatography coupled with high-resolution mass spectrometry (UPLC-HRMS). We measured the adsorption and desorption coefficients of three pesticides namely glyphosate, 2,4-D and difenoconazole for these soils. We developed Partial Least Square Regression (PLSR) models for the prediction of the sorption coefficients from the RT-m/z matrix and conducted further ANOVA analyses to identify, annotate and characterise the most significant constituents of SOM in the PLSR models. The curated metabolomics matrix yielded 1213 metabolic markers. The prediction performance of the PLSR models was generally high for the adsorption coefficients Kdads (0.3 < R2 < 0.8) and for the desorption coefficients Kfdes (0.6 < R2 < 0.8) but low for ndes (0.03 < R2 < 0.3). The most significant features in the predictive models were annotated with a confidence level of 2 or 3. The molecular descriptors of these putative compounds suggest that the pool of SOM compounds driving glyphosate sorption is reduced compared to 2,4-D and difenoconazole, and these compounds are generally more polar. This approach can provide estimates of the adsorption and desorption coefficients of pesticides, including polar pesticide, for contrasted pedoclimates.

Method Validation for the Determination of Glyphosate and Aminomethylphosphonic Acid in Water by LC-MS/MS

The massive use of glyphosate as a herbicide compound has led to the ubiquity of AMPA in the environment, especially in water. So, the present work aimed to establish the validation parameters of the LC-MS/MS method for glyphosate and its metabolite AMPA, determination in water. During the extraction process the derivatization of glyphosate as an extreme polar pesticide, was done using FMOC. The validation results show that the method met the criteria given in SANTE/11312/2021 for all the investigated validation parameters as well as estimated measurement uncertainty.

Development and inter-laboratory validation of analytical methods for glufosinate and its two metabolites in foods of plant origin.

Glufosinate is widely used to control various weeds. Glufosinate and its main metabolites have become the focus of attention because of their high water solubility and persistence in aquatic systems. Quantification of the agrochemical product and its metabolite residues is essential for the safety of agricultural products. In this study, a highly specific, simple method was developed to directly determine glufosinate and its metabolite residues in 21 plant origin foods by liquid chromatography with tandem mass spectrometry (LC-MS/MS), and it was validated on 11 foods in five laboratories. Finally, the repeatability limit, reproducibility limit, and uncertainty of the method were calculated based on these validated data and used to support the more accurate detection results. Four different chromatographic columns were used to analyze three target compounds, and the anionic polar pesticide column showed the optimum separation and peak shape. Composition of the mobile phase, extraction solvent, and the clean-up procedure were optimized. The developed method was validated on 21 plant origin foods. The average recoveries were 74-115% for all matrices. The validation results of five laboratories showed this method had a good repeatability (RSDr < 9.5%) and reproducibility (RSDR < 18.9%). The method validation parameters met the requirements of guidance established by the European Union (EU) and China for pesticide residue analysis. This methodology can be used for a routine monitoring that performs well forglufosinate and its metabolite residues.

Improved Method for the Detection of Highly Polar Pesticides and Their Main Metabolites in Foods of Animal Origin: Method Validation and Application to Monitoring Programme

The application of polar pesticides in agricultural production has been of great interest due to their low costs and their high effectiveness. For this reason, the possibility of their transfer to foods of animal origin is of great concern for human health. The manuscript describes the implementation and validation of an analytical method to detect polar pesticides, at regulatory levels, in three foods of animal origin, including bovine fat, chicken eggs, and cow milk. The method was fully validated to detect glyphosate, glufosinate, and their respective metabolites in the above-mentioned foods obtaining fit-for-purpose sensitivity, recoveries (76–119%), repeatability (≤20%), within-laboratory reproducibility (≤20%), and experimental measurement uncertainty less than 50% as required by the SANTE/11312/2021 criteria. Given the satisfactory results, the applicability of the method to additional molecules belonging to the same category (AMPA, cyanuric acid, ethephon, fosetyl aluminum, HEPA, maleic hydrazide, and N-acetyl-glyphosate) was also evaluated in order to meet possible future requests. Finally, the implemented method was applied to analyse samples over the period of March 2021 to August 2022 from two Italian regions (Umbria and Marche) within the national monitoring programme. In agreement with previously available data, none of the samples analysed showed the presence of glyphosate and glufosinate at levels above the legal limit.

An analytical method for the determination of glyphosate and aminomethylphosphoric acid using an anionic polar pesticide column and the application in urine and serum from glyphosate poisoning patients.

An analytical method for the determination of glyphosate (GLY) and aminomethylphosphoric acid (AMPA) in biological fluid samples (serum and urine) from poisoning patients using liquid chromatography-tandem mass spectrometry (LC-MS/MS) is established. After the sample pretreatment, including protein precipitation and a modified liquid-liquid extraction method, the chromatographic separation was conducted on a trifunctional modified hydrophilic column. The mobile phases in the gradient program were 2.5% formic acid aqueous solution and acetonitrile. The multiple reaction monitoring (MRM) models and the isotope-labeled internal standards were used in the acquisition process. Good linearities and satisfying recovery rates were obtained in two sample matrices with good RSDs. The detection limits of GLY and AMPA were <2 μg L-1, which were close to those obtained in our previous research. The established method was applied to biological samples from five patients with glyphosate intoxication. The analysis of the trend for the concentration of GLY and AMPA in two biological samples was investigated, and the difference in the downward trend of AMPA in urine was found in patients with a relatively higher concentration of GLY in serum.

Monitoring and Exposure Assessment of Fosetyl Aluminium and Other Highly Polar Pesticide Residues in Sweet Cherry.

Cherries are popular fruits due to their health benefits, organoleptic quality, and attractive appearance. Since highly polar pesticides are of low mass and amphoteric character, and are not amenable to traditional multi-residue extraction methods, they are more commonly not included in the pesticide monitoring program. This study aims to determine twelve highly polar pesticide residues in cherry samples intended for export from Turkey. A total of 16,022 cherry samples from 2018-2020 harvests in four production areas of Turkey were analyzed using a modification of the Quick Polar Pesticides method and liquid chromatography-tandem mass spectrometry. The method was validated at two fortification levels (0.01 and 0.05 mg kg-1), and good recoveries (87.4-111.4%) and relative standard deviations (&lt;6%) were achieved for all analytes. The limits of quantification were in the range of 1.08-2.55 μg kg-1. Overall, 28.4% of the analyzed cherry samples were detected with phosphonic acid, calculated as fosetyl aluminium (fosetyl-Al) in amounts up to 77.7 mg kg-1. For 2304 samples (14.4%), the residues exceeded the European Union maximum residue level of 2 mg kg-1. There is no reason to be concerned about long-term exposure to phosphonic acid/fosetyl-Al, and the other highly polar pesticides through the consumption of sweet cherry.

Determination of glyphosate and AMPA in indoor settled dust by hydrophilic interaction liquid chromatography with tandem mass spectrometry and implications for human exposure

The widespread application of glyphosate leads to significant contamination of outdoor environmental compartments, notably air and soil, which can contaminate indoor air and dust. This study assessed the contamination of indoor household dust for the first time in France and potential exposure to glyphosate through the inadvertent ingestion of dust. A specific and new analytical method was developed using HILIC MS/MS (hydrophilic interaction liquid chromatography with tandem mass spectrometry) to measure polar pesticides, such as glyphosate, aminomethylphosphonic acid, and glufosinate, in indoor dust, with a low quantification limit (25 ng/g). The dust from vacuum cleaner bags of 60 rural and urban households (Brittany, France) was analyzed. All samples contained glyphosate (median 1675 ng/g for rural dwellings (n = 29), 457 ng/g for urban dwellings (n = 31)), more than 90 % contained aminomethylphosphonic acid, and none contained glufosinate. Concentrations were influenced by the rural or urban setting, the proximity of crops, and the use of weed killers on driveways or lawns. Glyphosate exposure via indoor dust ingestion was < 1 % of both acceptable daily intake and dietary intake. However, the high quantification limit of the glyphosate concentration in the food analysis method probably leads to overestimation of the dose from food.

Analysis of highly polar pesticides in foods by LC-MS/MS.

Highly polar pesticides (HPP) are a group of pesticides that are characterize as low Log Kow. Many high-throughput multi-residue analysis methods based on liquid chromatography-tandem mass spectrometry (LC-MS/MS) for the simultaneous determination of such polar pesticides have been proposed. In this article, we summarize the various sample preparation methods including quick polar pesticides (QuPPe), dispersive solid phase extraction (dSPE), solid phase extraction (SPE) and QuEChERS (Quick, Easy, Cheap, Effective, Rugged and Safe), especially for QuPPe, which are mainly used for the determination of HPP in foods. In addition, we summarize LC-based separation methodologies that are currently used for the analysis of HPP in foods, including reversed-phase chromatography (RPC), hydrophilic interaction liquid chromatography (HILIC), ion chromatography (IC) and mixed-mode chromatography (MMC). Finally, the current mass spectrometry-based methodologies for the analysis of HPP are summarized with a specific focus on MS configurations and acquisition modes.

Direct determination of glyphosate, aminomethylphosphonic acid and glufosinate in food samples with ion chromatography coupled to electrospray ionization tandem mass spectrometry

A fast and reliable method for the direct determination of the herbicide glyphosate, its major degradation product aminomethylphosphonic acid (AMPA) and glufosinate is presented for a variety of food matrices. The Quick Polar Pesticides in food of Plant Origin method (QuPPe-PO-Method) was used for extraction without further preconcentration or clean-up steps involving e.g. solid phase extraction (SPE). The method makes use of a commercially available high performance liquid chromatograph coupled to a tandem mass spectrometer with electrospray ionization (LC-ESI-MS/MS) - as present in many laboratories - equipped with an ion chromatography (IC)-column using an MS-compatible eluent made of 0.8% formic acid in water. Due to the absence of time-consuming clean-up procedures, strong matrix effects (ME) of up to 91% for AMPA in grapefruit can be observed, when comparing its sensitivity to that obtained for solvent-based standards. The limits of detection (LODs) were determined for the sample matrices apple, mushrooms, grapefruit, linseed, red lentils and wheat and they were found to be in the range of 0.09 to 0.8, 0.04 to 1 and 0.2 to 2 µg/kg for glyphosate, AMPA and glufosinate, respectively. For the same matrices the validation was carried out according to SANTE guidelines for different commodity groups by spiking them up prior to extraction to concentrations ranging from 10 to 400 µg/kg for matrices with high water content and from 10 to 800 µg/kg for matrices with low water content. When using solvent-based calibration under the use of isotopically labelled internal standards (ILIS) the recoveries were found to range from 84% to 120% and the relative standard deviations (RSD) range between 1% and 19% for glyphosate, AMPA and glufosinate at all fortification levels for all matrices investigated. Accordingly, the method was successfully introduced in our laboratory with limits of quantification (LOQs) of 10 µg/kg for glyphosate, AMPA and glufosinate in samples from SANTE commodity groups 1, 2, 4a and 5. The reliability and robustness of the method are demonstrated by showing a recovery control chart obtained for glyphosate in randomly selected samples from different commodity groups. Therefore, the samples were spiked up with 10 µg/kg of glyphosate during routine analysis, whereby all recoveries were found to be in the range between 70 and 120%.

Occurrences, distribution and risk assessment of polar pesticides in Niger River valley and its tributary the Mekrou River (Niger Republic).

The increase in food needs due to high population growth in Niger has led to the intensification of urban agriculture and the increased use of pesticides. The objective of this study is primarily to assess the polar pesticide contamination (mainly herbicides) of the Niger River and its tributary, the Mekrou River, in Niger, using both grab sampling and POCIS (Polar Organic Chemical Integrative Samplers), and then to evaluate the risk to the aquatic environment. Two water sampling campaigns were carried out during the wet and dry seasons. The polar pesticides were analyzed by liquid chromatography coupled with tandem mass spectrometry, which allowed the identification of compounds with concentrations in the grab samples above the WHO guide values and the EU directive: diuron with 2221ng/L (EU quality guideline: 200ng/L), atrazine with 742ng/L (EU quality guideline: 600ng/L) and acetochlor with 238ng/L (EU quality guideline: 100ng/L). The risk assessment study indicated that diuron and atrazine present a high risk for the aquatic environment during the wet season. The main source of water contamination is the intensive use of pesticides in urban agriculture near the city of Niamey, and the intensive cotton farming in the Benin. Moreover, the surveys (30 producers interviewed) showed that 70% of the pesticides used are not approved by the Interstate Committee for Drought Control in the Sahel (CILSS) and some are prohibited in Niger. The inventory of pesticides sold in the zone showed that active ingredients used by producers are 48% insecticides, 45% herbicides, and 7% fungicides.

Agro-ecological risk of pesticides application for protecting apple plantations in the conditions of Pre-Carpathian Province of the Carpathian mountains in Ukraine

It was found that the rate of detoxification of pesticides depends on their physicochemical properties and correlates with the polarity of the compounds. According to the magnitude of dipole moments, the studied pesticides are divided into three groups: nonpolar with µ from 0 to 2 Debye (D), low-polar with µ from 2 to 6 Debye and polar with µ more than 6 Debye. Non-polar pesticides are practically insoluble in water and their decay period in the ecosystem is longer than that of low-polar and polar pesticides. Peculiarities, speed and dynamics of pesticide detoxification in the apple orchard ecosystem have been studied. It was found that non-polar pesticides decompose at a rate of 0.07–0.12±0.05 parts per day, and low-polar pesticides — at a rate of 0.15–0.22±0.05 parts per day. On the tenth day after spraying, 0.05 to 1.24 mg/kg of the studied pesticides were detected in apple fruits and from 0.15 to 4.41 mg/kg in apple leaves. The classification of pesticides according to the degree of danger was carried out and it was found that the studied drugs have a degree of danger from 3 to 6. Pesticides with 3 degrees of danger are more dangerous to humans and biota and require more detailed regulation, regulation and control. The seasonal load of pesticides (H) for the intensive chemical system was 29.5 kg/ha, for the advanced system — 10.5 kg/ha and for the system of biological and chemical protection — 0.45 kg/ha. The weighted average hazard (Q) in the intensive chemical protection system was 5.0, for the advanced system — 4.9, and for the biological and chemical protection system — 6.8. It was found that the agroecotoxicological index for all protection systems was less than 1, all protection systems are not very dangerous and do not lead to ecosystem pollution. For the intensive system of chemical protection, this figure ranged from 0.24 to 0.49, for the advanced — from 0.014 to 0.025, and for the system of biological and chemical protection — from 6·10–5 to 8·10–5.

Selective isolation of pesticides and cannabinoids using polymeric ionic liquid-based sorbent coatings in solid-phase microextraction coupled to high-performance liquid chromatography

The high abundance of cannabinoids within cannabis samples presents an issue for pesticide testing as cannabinoids are often co-extracted with pesticides using various sample preparation techniques. Cannabinoids may also chromatographically co-elute with moderate polarity pesticides and inhibit the ionization of pesticides when using mass spectrometry. To circumvent these issues, we have developed a new approach to isolate commonly regulated pesticides and cannabinoids from aqueous samples using tunable, crosslinked imidazolium polymeric ionic liquid (PIL)-based sorbent coatings for direct immersion solid-phase microextraction (DI-SPME). The selectivity of four PIL sorbent coatings towards 20 pesticides and six cannabinoids, including cannabidiol and Δ9-THC, was investigated and compared against a commercial PDMS/DVB fiber. Extraction and desorption conditions, including salt content, extraction temperature, pH, extraction time, desorption solvent, and desorption time, were optimized using high-performance liquid chromatography (HPLC) with ultraviolet (UV) detection. Under optimized conditions, the PIL fiber consisting of 1-vinylbenzyl-3-octylimidazolium bis[(trifluoromethyl)sulfonyl]imide ([VBIMC8+][NTf2−]) and 1,12-di(3-vinylbenzylimidazolium)dodecane dibis[(trifluoromethyl)sulfonyl]imide ([(VBIM)2C122+]2[NTf2−]) sorbent coating provided the best selectivity towards pesticides compared to other PILs and the PDMS/DVB fibers and was able to reach limits of detection (LODs) as low as 1 µg/L. When compared to a previously reported PIL-based SPME HPLC-UV method for pesticide analysis, the amount of cannabinoids extracted from the sample was decreased 9-fold while a 4-fold enhancement in the extraction of pesticides was achieved. Additionally, the PIL-based SPME method was applied to samples containing environmentally-relevant concentrations of pesticides and cannabinoids to assess its feasibility for Cannabis quality control testing. Relative recoveries between 95% and 141% were obtained using the PIL sorbent coating while recoveries ranging from 50% to 114% were obtained using the PDMS/DVB fiber.

Geochemical matrix differently affects the response of internal standards and target analytes for pesticide transformation products measured in groundwater samples

Electrospray ionization (ESI) is the most common technique in liquid chromatography coupled to tandem mass spectrometry (LC-MS-MS) allowing for sensitive detection of polar compounds with online water concentration. The technique is popular in groundwater monitoring programs and has permitted great progress in the detection and quantification of polar pesticide transformation products (TP) in recent years. However, ESI is also known to be prone to matrix effects. The common solution to this potential bias is the use of labelled internal standards. Unfortunately, these are not available for all target compounds, which leads to the linkage of target compounds to non-homologue internal standards with unknown consequences for quantification in variable geochemical settings. We investigated these matrix effects for polar TP with a molecular mass range of 225–350 Da and logDpH7 between −0.27 and −1.7 as well as for parent compounds with logDpH3 between 0.84 and 3.22. The acquired internal standards were tested on a gradient of DOC, anions, conductivity and inorganic carbon with a set of ten carefully chosen groundwater samples. Internal standards that were measured in positive ionization mode proved to be insensitive to geochemical variations while those that were measured in negative ionization mode showed reduced response with increasing anion concentration. All pairs of internal standards and target analytes were investigated for deviating matrix effects using standard addition experiments. Positive ionization compounds and target compounds with deuterated homologues showed little deviation while non-homologue pairs in negative mode proved to be strongly biased. Although bias was up to factor five for some compounds it was remarkably stable over the entire gradient studied, suggesting an identical suppression mode at varying matrix levels for different compounds. We advocate the conduct of standard addition experiments if homologue internal standards are not available.

Pesticide fate during drinking water treatment determined through passive sampling combined with suspect screening and multivariate statistical analysis

Emerging contaminants such as polar pesticides pose a potential risk to human health due to their presence in drinking water. However, their occurrence and fate in drinking water treatment plants is poorly understood. In this study we use passive sampling coupled to suspect screening and multivariate analysis to describe pesticide fate throughout the treatment stream of an operational drinking water treatment plant. ChemcatcherÒ passive sampling devices were deployed at sites (n = 6) positioned at all stages of the treatment stream during consecutive deployments (n = 20) over a twelve-month period. Sample extracts (n = 120) were analysed using high-resolution liquid chromatography-quadrupole-time-of-flight mass spectrometry and compounds identified against a commercially available database. A total of 58 pesticides and transformation products from different classes were detected. Statistical analysis of the qualitative screening data was performed to identify clusters of pesticides with similar fate during ozonation, granular activated carbon (GAC) filtration, and chlorination. The performance of each treatment process was investigated. Adsorption to GAC media was found to account for the greatest proportion of pesticide attenuation (average removal of 70% based on detection frequency), however, operational performance varied for certain pesticides during periods of episodic and sustained pollution. GAC breakthrough occurred for 21 compounds detected in the GAC filtrate. Eleven pesticides were found to occur in potable water following treatment. We developed a management plan containing controls, triggers, and responses, for five pesticides and a metabolite (atrazine, atrazine desethyl, DEET, dichlorobenzamide, metazachlor, and propyzamide) prioritised based on their current and future risk to treated water quality.

Development of a Quantitative Method for Detection of Multiclass Veterinary Drugs in Feed Using Modified QuPPe Extraction and LC-MS/MS.

A method was developed for the rapid and quantitative analysis of 30 veterinary drugs belonging to 17 classes (amphenicols (1), anthelmintics (1), cephalosporins (4), coccidiostats (1), lincosamides (1), macrolide (1), nitroimidazole (1), penicillins (3), phenylhydrazines (1), polypeptides (1), pyrethrins (1), quinolones (5), sulfonamides (3), tetracycline (3), neuroleptic agents (1), triazene trypanocidal agents (1), other. (1)) in feeds. The proposed method with a modified Quick Polar Pesticides (QuPPe) sample preparation was validated for the determination of 30 veterinary drugs in feed samples by liquid chromatography triple-quadrupole mass spectrometry (LC–MS/MS). The sample was extracted with methanol containing 1% acetic acid and purified by dispersive solid-phase extraction (d-SPE) with C18. Good linearity (r2 ≥ 0.98) was observed, and the LOQ values ranged from 10 to 200 µg/kg. Average recoveries ranged from 70.8 to 118.4%, and the relative standard deviation was ≤ 18.7%. This validated method was used in the determination of 30 veterinary drugs in 142 feed samples obtained from South Korea. The results show that lincomycin was present in only one of the tested feed samples, although it was detected at a value lower than the LOQ. In conclusion, this multi-residue method can be used for screening through the detection and quantitation of residual multiclass veterinary drugs in feed samples.

Airborne polar pesticides in rural and mountain sites of North-Eastern Italy: An emerging air quality issue

North-Eastern Italy and in particular Veneto Region, stands out as a major centre of agriculture and viticulture which has rapidly expanded in the last decade with high productivity indexes. In this context, assessing atmospheric pollution caused by crop spraying with pesticides in rural areas and their transport to high-altitude remote sites is crucial to provide a basis for understanding possible impacts on the environment and population health. We aim to improve existing methods with a highly sensitive technique by using high pressure anion exchange chromatography coupled to a triple quadrupole mass spectrometer. Thus, a total of fourteen polar pesticides were determined in aerosol samples collected from August to December 2021 at Roncade (Venetian plain) and Col Margherita Observatory (Dolomites). The observatory was chosen as the background site as it is representative of the surrounding alpine region. Some samples revealed a substantial amount of cyanuric acid mainly at Roncade (mean concentration of 10 ± 10 ng m−3), glyphosate and fosetyl-aluminium (0.1 ± 0.2 and 0.1 ± 0.1 ng m−3, respectively). Surprisingly, some pesticides have been also found at Col Margherita, a high mountain background site, with concentrations an order of magnitude lower than at Roncade. This is the first time that fourteen polar pesticides have been assessed in the aerosol phase of the Po’ Valley and detected at a high-altitude remote site, and consequently this study provides the first data on their occurrences in Italian aerosols. It represents a basis for the assessment of risks for humans.

The Current Status of Analytical Methods Applied to the Determination of Polar Pesticides in Food of Animal Origin: A Brief Review.

The use of high polar pesticides such as glyphosate and metabolites has increased due to their low cost, low persistence in the environment and high effectiveness. The use of glyphosate is currently permitted in the European Union until 15 December 2022. However, the possible toxic effects on human health and the environment are under debate. Their widespread application on various crops might lead to residues in food intended for animal consumption. For this reason, the Commission, implementing Regulation (EU) 2021/601, recommends the analyses of polar pesticides, not only in matrices of plant origin, but also in those of animal origin such as fat, liver, milk and eggs throughout the years 2022, 2023 and 2024. The determination of polar pesticides is hampered by their chemical nature, which poses challenges both in the instrumental detection (poor column retention, low molecular weight MS/MS fragments, etc.) and in the management of matrix effects, which may vary significantly from matrix to matrix within the same food commodity group. For these reasons, nowadays, there is a limited number of methods for the detection of polar pesticides in food of animal origin. This brief review discusses the different approaches for the simultaneous determination of polar pesticides in food of animal origin using both chromatographic and non-chromatographic techniques.

A Continuous Flow Injection/Indirect Photometric Method for the Detection of Fosetyl Aluminum in Commercial Pesticide Formulations

AbstractBecause of their Physico‐chemical characteristics and its composition, the development of new specific analytical methodologies to determine some highly polar pesticides are required. The reported methods demand long analysis time, expensive instruments and prior extraction of pesticide for detection. The current work presents a new flow injection analysis method combined with indirect photometric detection for the determination of Fosetyl‐Aluminum (Fosetyl‐Al) in commercial formulations, with rapid and highly accurate determination involving only construction of manifold system combined with photometric detector without need some of the pre‐treatments to the sample before the analysis such as extraction or separation. The proposed method is based on the reaction between the Fosetyl‐Al with the colorimetric reagent (Aluminon dye) in an aqueous medium of sodium nitrite resulting in the formation of a red complex and its absorbance is measured using the photometric detector. The proposed method included optimization of several parameters such as sodium nitrite concentration, flow rate, sample volume, Aluminon dye concentration, mixing coil and light intensity. The linear range of the detector response was in the range of 0.005–1.8 mmol/L for the sample with r (coefficient of determination) 0.9909, R2 (correlation coefficient) 0.9954 at 95 % and 0.0041 mmol/L as a limit of detection. The relative standard deviation was less than 1.5 % for 0.005 mmol/L of the analyte (n=11). The proposed method was validated and applied successfully for the determination of Fosetyl‐Al in commercial formulations and can be used as an alternative method for quality control assessment.

Pesticides in sediments of the Ebro River Delta cultivated area (NE Spain): Occurrence and risk assessment for aquatic organisms

Intense agricultural activities are performed in the Ebro River Delta (NE Spain) with extensive use of pesticides. Medium to highly polar pesticides have not been studied intensively in sediments despite its larger use in the recent years. This work aimed at assessing the occurrence of 69 pesticides, including medium to highly polar compounds, in sediments collected from drainage and irrigation channels of the Ebro River Delta during the main rice growing season. In addition, an environmental risk assessment was performed to evaluate the potential adverse effects to sediment-dwelling organisms with the risk quotient approach. A total of 24 pesticides were detected in sediments with bentazone and cypermethrin exhibiting high detection frequencies (79%) as well as high mean concentration levels (61.9 and 81.8 ng g−1 dw, respectively). Overall, the Alfacs bay, in the South of the delta, presented higher pesticide contamination than the Fangar bay, in the North. A similar pesticide distribution profile was observed in both bays, with oxadiazoles, organochlorines, pyrethroids, benzothiazinones and organophosphates as major, predominant classes. The presence of oxadiazon, pendimethalin and thifensulfuron methyl in the sediments may pose a moderate risk to sediment-dwelling organisms while bentazone, chlorpyrifos, and cypermethrin exhibited a potential high risk. Thus, the importance of the inclusion of medium to highly polar pesticides in the analysis of sediments is emphasized since some polar pesticides such as bentazone, imidacloprid, and thifensulfuron-methyl have been detected at concentrations that may pose a risk to aquatic organisms. Moreover, the co-occurrence of pesticides may potentially pose a high risk to sediment-dwelling organisms in 13 out of the 14 investigated locations. Finally, it could be concluded that the risk derived from the presence of pesticides in sediments must be assessed since some pesticides not detected at concerning levels in water, may pose a moderate/high risk in the sediments.

Quick Polar Pesticides (QuPPe): Learning from and Expanding on the Work of Others

In January, Steve Lehotay from the U.S. Department of Agriculture provided an update on the quick, easy, cheap, effective, rugged, and safe (QuEChERS) extraction method, originally developed for multiresidue pesticide analysis. Like any method, QuEChERS had some deficiencies, which were addressed with the new QuEChERSER (adding “efficient” and “robust” to the acronym) mega-method. Meanwhile, the European Union (EU) Reference Laboratories developed a new method for the multiresidue analysis of highly polar pesticides, called the quick polar pesticides (QuPPe) method. This month, we take a look at QuPPe, comparing and contrasting it with QuEChERS and noting how we can learn from previously developed methods as we strive for improvements.