Target Pesticides Research Articles

Simultaneous determination and exposure assessment of six common pesticides in greenhouses through modified QuEChERS and gas chromatography–mass spectrometry

Owing to the excessive use of pesticides in greenhouses, soils and vegetables herein are more heavily contaminated than those in non-facility cultivation. Based on a developed QuEChERS (quick, easy, cheap, effective, rugged, and safe) method, four methods of sample pretreatment were compared for the monitoring of six pesticides (bifenthrin, chlorfenapyr, lambda-cyhalothrin, pyridaben, pyrimethanil, and pyriproxyfen) commonly used in greenhouses of Hubei Province. Using different extraction strategies and purification methods with different solid phases and eluent mixtures, an optimised method for residual analysis in soil and plant samples via gas chromatography–mass spectrometry was determined. The detection limits of the method for the six pesticides ranged from 0.1 to 0.8 µg/kg in three spiked matrixes and average recovery rates of 80.6–118.3% were achieved for single target pesticides at spiked concentrations of 0.1, 1.0, and 10 mg/kg with standard deviations of 2.4–8.4%. Health risk assessment was conducted through the analysis of greenhouse soil and vegetable samples at Pengdun, a typical agricultural greenhouse facility in Jingmen, Hubei Province, central China. Based on the quantification of the six target compounds in four vegetable types, only pyriproxyfen in tomato exceeded the Canadian and WHO/FAO maximum residue limits. No chronic, acute, non-carcinogenic, or carcinogenic health risks to farmers working in the greenhouses or consumers of the vegetables were observed for all age groups in the study area. Residual results showed that pyridaben is the most often quantified pesticide in all greenhouses of the study area. Pesticide combinations, including bifenthrin, chlorfenapyr, and pyridaben, were similar for cucumbers and eggplants. Nevertheless, simultaneous detection of multiple contaminants and health risk assessment are required because combined contamination may lead to much higher toxicity to both workers and consumers with the emergence of pesticide resistance and the development of new pesticide products. The quantification limits of the developed method for the simultaneous analysis of the six target pesticides showed high reliability, accuracy, effectiveness, and applicability.

Improved fully automated method for the determination of medium to highly polar pesticides in surface and groundwater and application in two distinct agriculture-impacted areas.

Water is an essential resource for all living organisms. The continuous and increasing use of pesticides in agricultural and urban activities results in the pollution of water resources and represents an environmental risk. To control and reduce pesticide pollution, reliable multi-residue methods for the detection of these compounds in water are needed. In this context, the present work aimed at providing an analytical method for the simultaneous determination of trace levels of 51 target pesticides in water and applying it to the investigation of the target pesticides in two agriculture-impacted areas of interest. The method developed, based on an isotopic dilution approach and on-line solid-phase extraction-liquid chromatography-tandem mass spectrometry, is fast, simple, and to a large extent automated, and allows the analysis of most of the target compounds in compliance with European regulations. Application of the method to the analysis of selected water samples collected at the lowest stretches of the two largest river basins of Catalonia (NE Spain), Llobregat and Ter, revealed the presence of a wide suite of pesticides in the Llobregat basin, some of them at concentrations above the water quality standards (irgarol and dichlorvos) or the acceptable method detection limits (methiocarb, imidacloprid, and thiacloprid), and much cleaner waters in the Ter River basin. Risk assessment of the pesticide concentrations measured in the Llobregat River indicated high risk due to the presence of irgarol, dichlorvos, methiocarb, azinphos ethyl, imidacloprid, and diflufenican (hazard quotient (HQ) values>10), and moderate potential risk in the Ter River, associated to the occurrence of bentazone and irgarol (HQ > 1).

Modified QuEChERS extraction method followed by simultaneous quantitation of nine multi-class pesticides in human blood and urine by using GC-MS

Organophosphate, carbamate and pyrethroid pesticides are the most common insecticides used worldwide. They may cause chronic poisoning in farmers and acute poisoning in homicidal or suicidal cases. The determination of trace levels of these pesticides in human blood and urine is very challenging. This study focuses on a simultaneous quantitation method that was developed and validated for multi-class nine pesticides belonging to organophosphate, carbamate and pyrethroid classes in human blood and urine. Target pesticides were extracted from blood and urine using a modified QuEChERS (Quick, Easy, Cheap, Effective, Rugged and Safe) extraction method. Capillary column DB-35 ms (15 m × 0.25 mm, 0.25 µm) was used for chromatography with a 0.079 ml/min flow rate of carrier gas at constant pressure mode. Quantitation of sulfotep, phorate, carbofuran, chlorpyriphos, profenophos, triazophos, pyriproxyfen, lambda-cyhalothrin and permethrin was performed by mass spectrometer equipped with electron impact ionization source using selected ion monitoring (SIM) mode. The lower and upper limits of quantitation for all nine pesticides were 0.01 mg/L and 2.0 mg/dL respectively. The proposed method was proved to be simple, fast, sensitive, and robust. It has been applied to the analysis of 9 pesticides samples.

Reducing toxicity and antimicrobial activity of a pesticide mixture via photo-Fenton in different aqueous matrices using iron complexes

This is the first study to investigate ethylenediamine-N,N′-disuccinic acid (EDDS)/photo-Fenton process to polish real wastewater containing pesticides for possible water reuse. To this end, simultaneous degradation of pesticides ametrine, atrazine, imidacloprid and tebuthiuron was evaluated in distilled water (DW) and in sewage treatment plant (STP) effluent at initial pH 6.0. Several operational parameters (Fe3+-EDDS concentration, Fe3+-EDDS molar ratio, EDDS addition patterns and radiation source) were evaluated. 80–98% removal of target pesticides were obtained in DW using 30 μmol L−1 of Fe3+-EDDS with a molar ratio of 1:2 (300 μmol L−1 of H2O2). In addition, the proposed Fe3+-EDDS photo-Fenton at pH 6 was more efficient than classic photo-Fenton at pH 2.7 (30–84% removal). Experiments conducted in the presence of radical trapping agents (2-propanol or chloroform) revealed that HO• was the most active radical during treatment. Matrix composition strongly affected the degradation of target pesticides as a six-fold higher concentration of reagents (180 μmol L−1 of Fe3+-EDDS and 1800 μmol L−1 of H2O2) was needed to reach the same efficiency in STP compared to DW. Even so, first order rate constants corresponding to the degradation of pesticides in DW (k = 0.098–0.85 min−1) were nearly two-fold higher than in STP (k = 0.079–0.49 min−1) under the same radiation source (black-light or solar radiation). Finally, acute toxicity towards Vibrio fischeri and Drosophila melanogaster flies, and antibacterial activity assessed for Escherichia coli were eliminated after the application of the proposed treatment, thus indicating environmental safety for either discharge or reuse of treated wastewater for crop irrigation in agriculture.

A survey of 59 pesticide residues in Turkish chicken eggs using LC-MS/MS

ABSTRACT An LC-MS/MS multi-residue method was validated for the determination of 59 pesticide residue levels in a chicken egg by using QuEChERS extraction method. The validation parameters used were taken from the SANTE/11813/2017 guideline. The calibration curves for each target pesticide had a good linearity in a range of 1.0 or 2.5 to 100.0 µg kg−1 (r2 ≥ 0.995). Ten per cent of the total pesticides had LOQ values less than 5.0 µg kg−1 or LOQ values from 5.0 to 10.0 µg kg−1. The LOQ values were below the MRLs set by the European Commision (EC). Average recoveries (70–120%) and relative standard deviations (RSDs≤20%) were achieved for 59 selected pesticides at different concentrations (5 or 10 and 200 µg kg−1). All expanded measurement uncertainties were lower than 50%. The occurrence of these pesticides was evaluated in 35 commercially available chicken eggs. No MRL exceedance was identified.

Polymeric ionic liquid sorbent coatings in headspace solid-phase microextraction: A green sample preparation technique for the determination of pesticides in soil

In this work, a green approach utilizing novel polymeric ionic liquid (PIL) coatings for headspace solid-phase microextraction (HS-SPME) of four current-use pesticides from soil samples was studied for the first time. Epoxiconazole, fluroxypyr, metribuzin, and oxyfluorfen were the target pesticides. Three PIL coatings containing 1-vinylbenzyl-3-hexadecylimidazolium bis[(trifluoromethyl)sulfonyl]imide (PIL1 and PIL2) and 1-vinyl-3-(10-hydroxydecyl)imidazolium bis[(trifluoromethyl)sulfonyl]imide (PIL3) monomers, and 1,12-di(3-vinylbenzylimidazolium)dodecane bis[(trifluoromethyl)sulfonyl]imide (PIL1) and 1,12-di(3-vinylbenzimidazolium)dodecane bis[(trifluoromethyl)sulfonyl]imide (PIL2 and PIL3) crosslinkers were employed in this study. The performance of these PIL coatings was evaluated and compared with commercial SPME coatings based on polydimethylsiloxane/divinylbenzene (PDMS/DVB) and polydimethylsiloxane (PDMS) at the different extraction temperatures (50–90 °C) and sampling times (15–60 min). HS-SPME at 90 °C for 60 min provided the highest sensitivity and adequate reproducibility for the majority of analytes. Despite having a lower thickness, PIL2 and PIL3 coatings provided similar extraction effectiveness of analytes, and 24–247% higher coating volume-normalized responses compared to the commercial PDMS/DVB coating. The use of the PIL1 sorbent coating resulted in excellent linearity (R2 = 0.995–0.999) and lower detection limits (0.06–0.4 ng g−1) for all analytes. The optimized method provides acceptable recoveries of spiked concentrations with better performance (84–112%) achieved with the PIL1 coating. Compared to other known methods for target pesticides in soil, the proposed method provides the highest compliance with the principles of green analytical chemistry evaluated using Analytical Eco-Scale and Green Analytical Procedure Index tools.

Exogenous salicylic acid mitigates the accumulation of some pesticides in cucumber seedlings under different cultivation methods.

Salicylic acid (SA) is a crucial signal molecule and phytohormone, regulating the biotic and abiotic stress responses as well as plant development. In this research, we comparatively examined the effects of exogenous SA on the behaviors of thiamethoxam (THIM), hymexazol (HMI) and chlorantraniliprole (CAP) in cucumber planting systems under soil pot and hydroponic cultivation. The cucumber seedlings were transplanted into soil or nutrient solution containing a target pesticide (1mg/kg) or a target pesticide with SA (1mg/kg) after the fourth leaf emerged. We examined the behaviors of pesticides both the SA treated and nontreated plants by analyzing cucumber root, stem and leaf samples taken on the 0-21 days following the root treatment. The root concentration factor (RCF), bioconcentration factor (BCF) and translocation factors (TFstem and TFleaf) were calculated for the comparison of the differences in the behaviors of pesticides. We found that the accumulation behaviors of pesticides in planting systems were related to the physicochemical properties of pesticides, exogenous SA and cultivation methods. Exogenous SA had a certain promoting effect on the degradation of pesticides in soil and nutrient solution, resulting in reduced half-lives. SA was able to block the accumulation of pesticides in roots and leaves and alleviated the accumulation ability of roots, the bioconcentration ability of plants, and the translocation ability from roots to leaves. Interestingly, SA had more distinct effects on the behaviors of pesticides under hydroponic experiments than under soil pot experiments. Furthermore, the behaviors of clothianidin (CLO), the main metabolite of THIM, were also assessed, indicating that THIM was mainly metabolized to CLO in leaves and stems, and SA facilitated this process. Our findings suggest that SA has a certain regulatory effect on the accumulation of pesticides in plants, and SA-blocked pesticide accumulation is practically rewarding for improving food safety.

Multi-Residue Screening of Pesticides in Aquaculture Waters through Ultra-High-Performance Liquid Chromatography-Q/Orbitrap Mass Spectrometry

Pesticide residues in foodstuffs can lead to several undesirable effects. A simple and high-throughput targeted screening method analyzing multi-residue pesticide in aquaculture water based on ultra-high-performance liquid chromatography-Q/Orbitrap mass spectrometry (UHPLC-Q/Orbi MS) was developed and validated. In this technique, the peaks of the compound using precursor ions were recorded by the full scan, which was used for rough quantitative analysis with single point matrix matched calibration. The qualitative identification was performed following the stringent confirmation criteria with fragment ions, retention time, and an isotopic pattern. Additionally, solid-phase extraction with an HLB (Hydrophilic/Lipophilic Balanced) column was selected to enrich and separate target pesticides from water. The screening detection limit of 33 compounds are less than 2 ng·L−1, while 26 compounds range from 2 ng·L−1 to 10 ng·L−1, 19 compounds are at the range of 10–200 ng·L−1, and the other two compounds are 200 ng·L−1 and 1000 ng·L−1. Most of the recovery results were found to be between 60~130%. Finally, the method was successfully applied to the analysis of pesticide residues in 30 water samples from aquaculture environment in Shanghai, indicating its applicability in pesticide screening for environmental monitoring.

An experimental and theoretical study of molecularly imprinted electrode based on methyl methacrylate polymer for pesticide detection

A selective electrode based on molecularly imprinted polymer (MIP) was developed by the polymerization of methyl methacrylate polymer on a screen-printed electrode for pesticide detection. Cypermethrin is one of the pesticides in the pyrethroid group, which has high toxicity in an organism and humans and causes environmental pollution. Cypermethrin-MIP and non-imprinted polymer films on electrodes were characterized for their surface morphology. The electrochemical analysis of cypermethrin pesticide was measured by amperometry under the potential of −0.23 V versus Ag/AgCl. Decreasing the current was directly proportional to the concentration of cypermethrin in the range of 15.50 ppb–10.00 ppm, and the limit of detection value was calculated to be 15.00 ppb. The proposed modified electrode has high sensitivity of 0.094 μA ppm−1 and effective selective detection of cypermethrin in samples of real vegetable juice. The computational analyses were performed with the density functional theory at M06-2x/6-31 g(d,p), which predicted interaction and study mechanism between the MIP matrix with target pesticides.

Occurrences of 29 pesticides in the Huangpu River, China: Highest ecological risk identified in Shanghai metropolitan area

To investigate the occurrence and risk of pesticides in the Huangpu River basin, spatial and temporal concentration variations of 29 commonly used pesticides and their risk quotient (RQ) values for three different trophic organisms (fish, daphnia, green algae) from 16 sampling sites were conducted in 2018–2019. These 29 pesticides include 4 carbamates, 2 benzimidazoles, 6 neonicotinoids, 2 organophosphates, 9 triazoles, and 6 others. Of the 29 pesticides analyzed, 18 were present in every sample taken from the Huangpu River. The concentration of target pesticides in water samples ranged from < LOQ (for buprofezin in summer, autumn, and winter) to 607.30 ng L−1 (for carbendazim in spring). From the source (i.e., Taihu Lake) to the estuary of the Huangpu River, with the exception of isocarbophos and isoprothiolane (gradual decrease), the spatial variation of target pesticide concentrations firstly exhibited an increasing trend and then a decreasing trend. Peak spatial variation was seen in metropolitan area, which is closely related to the type of land use and the discharge of tributaries. In addition, the total summed concentration of the 29 pesticides during winter (1037.60 ng L−1) was higher than summer (788.82 ng L−1) in rural and metropolitan areas. For the ecological risk assessments of fish, daphnia, and green algae, the triazoles, carbamates, neonicotinoids were risk-dominant pesticides, respectively. Notably, carbendazim had a 100% detection frequency and the highest concentration of the 29 pesticides analyzed, indicating its high consumption in the Huangpu River basin.

Rapid analysis and residue evaluation of six fungicides in grape wine-making and drying

Rapid multianalysis methods of metalaxyl-M, boscalid, picoxystrobin, fluopicolide and its metabolite 2,6-dichlorobenzamide, pyraclostrobin, and mandipropamid in grapes, wine, and raisins were established. The residue determination of six fungicides in wine-making and fruit-drying processes and evaluation were studied. The six fungicides exhibited good linearity in all three matrices (r > 0.9953). The average recoveries of the six fungicides at three added levels were 78.8 %–106.3 % (RSD 0.6 %–12.5 %). During wine-making processes, metalaxyl-M dissipated slowly (T1/2 = 248 h), while the other five fungicides dissipated rapidly (T1/2 = 17−44 h). The transfer rates of the six fungicides in wine and pomace were 0.9 %–14 % and 22 %–72 %, respectively. During the drying process, the dissipation of metalaxyl-M was very limited, and the half-lives of the other five fungicides were 39−84 h. The processing factors (PFs) of the six fungicides during wine-making and drying were 0.01-0.19 and 0.35-0.97, respectively, which indicates that these processes can reduce the residues of these six fungicides in wine and raisins. The established multianalysis method provides a reference for the simultaneous detection of target pesticides in grape and its processed products. The residue determination results provide reasonable data for reducing pesticide residues and the dietary risk factors of grapes and their processed products.

Determination of Organophosphorus Pesticides in Juice and Water by Modified Continuous Sample Drop Flow Microextraction Combined with Gas Chromatography–Mass Spectrometry

In this paper, the technique of continuous sample drop flow microextraction (CSDF-ME) is developed by the addition of a narrow-necked conical vessel. In the developed technique, an organic solvent denser than water is used for the extraction of organophosphorus pesticides (OPPs) from fruit juice and river water, followed by analysis with GC-MS. Eight milliliters of the sample solution is pumped at 0.5 mL min−1 flow rate into 12.0 μL extraction solvent (chloroform) and placed in the narrow-necked conical vessel for extraction and pre-concentration processes. Under optimal condition, the enrichment factor (EF) and linearity are found to be in the range of 102–380 and 500.0 μg L−1 with correlation coefficient greater than 0.98, respectively. The detection limit is in the range of 0.3–1.0 μg L−1 and LOQ ranged from 2.0–5.0 μg L−1. The relative standard division (RSD) of six replicate measurements for three different concentrations (i.e., 15.0, 50.0, 150.0 μg L−1) is 3.8–8.4%, 2.6–6.0%, and 2.2–4.8%, respectively. Values of RSD% of the target pesticides at 50.0 μg L−1 concentration levels are less than 6.0%.

A global model for the determination of prohibited addition in pesticide formulations by near infrared spectroscopy

Generally, a pesticide was determined by a specific model, so different models were established for different pesticides as the backgrounds between pesticides formulations were with relatively huge discrepancy. It is expected to develop a more adaptive model which could not only improve the efficiency for prohibited addition detection but also afford an extensive application of the target pesticide. Moreover, less time would be spent on maintaining the model and thus the model supervision ability would be improve. In this paper, a global model for the determination of fipronil in a mixed matrix of imidacloprid and cypermethrin formulations was developed. The global model was established by means of two chemometrics methods, namely: full spectrum partial least squares (PLS) and competitive adaptive reweighted sampling-successive projections algorithm (CARS-SPA). Furthermore, the global model was investigated by the following two aspects: algorithm strategies of PLS and CARS-SPA, and spectroscopy interpretation. Results revealed that CARS-SPA combined with NIR could be efficiently used for rapid identification of prohibited addition in imidacloprid and cypermethrin formulations. Simultaneously, this study provided a theoretical support in the aspect of developing a global model for quantitative analysis.

Occurrence of pesticides in surface water, pesticides removal efficiency in drinking water treatment plant and potential health risk to consumers in Tengi River Basin, Malaysia

Agricultural activities have been arising along with the use of pesticides. The use of pesticides can impact not only on vector or other pest but also able to harm human health. Pesticide may leach from the irrigation of plant into the groundwater and in surface water. These waters could be sources of drinking water in a pesticides polluted area. This study aims to determine the occurrence pesticides in surface water and pesticides removal efficiency in a conventional drinking water treatment plant (DWTP) and the potential health risk to consumers. The study was conducted in Tanjung Karang, Selangor, Malaysia. Thirty river water samples and eighteen water samples from DWTP were collected. The water samples were extracted using solid phase extraction (SPE) before injected to the ultra-high performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS). Five hundreds and ten respondents were interviewed using questionnaires to obtain information for health risk assessments. The results showed that propiconazole had the highest mean concentration (4493.1 ng/L) while pymetrozine had the lowest mean concentration (1.3 ng/L) in river water samples. The pesticides removal efficiencies in the conventional DWTP were 77% (imidacloprid), 86% (propiconazole and buprofezin), 88% (tebuconazole) and 100% (pymetrozine, tricyclazole, chlorantraniliprole, azoxystrobin and trifloxystrobin), respectively. The hazard quotients (HQs) and hazard index (HI) for all target pesticides were <1, indicating there was no significant chronic non-carcinogenic health risk due to consumption of the drinking water. Conventional DWTP was not able to completely remove four pesticide; thus, advanced treatment systems need to be considered to safeguard the health of the community in future.

Analysis of Organochlorine Pesticides in Tomatoes Using a Modified QuEChERS Method Based on N-Doped Graphitized Carbon Coupled with GC-MS/MS

A modified QuEChERS protocol with a nitrogen-doped graphitized carbon derived from dicyandiamide sludge as a cleanup sorbent has been developed to determine 20 organochlorine pesticides in tomatoes using gas chromatography coupled to a triple-quadrupole mass analyzer. Compared with traditional QuEChERS adsorbents, N-doped graphitized carbon exhibited higher recoveries toward the target pesticides in tomatoes. And the modified protocol exhibited the advantages of environmental-friendly and low-cost. The use of dicyandiamide sludge to produce NGB as an adsorbent for QuEChERS opened up a new field for the comprehensive utilization of dicyandiamide waste. Under the optimum conditions, the modified method provided excellent linearity with correlation coefficient higher than 0.9980 and low limits of detection ranging from 0.001 to 0.1 μg/kg. The mean recoveries of the majority of pesticides in tomatoes ranged from 71.2 to 95.3% with relative standard deviation lower than 20%. Thus, the proposed protocol could be considered a good alternative for traditional QuEChERS method for pesticide analysis in agricultural vegetables.

Elucidation of False Detection of Pesticides During Residue Analysis in Indian Tobacco by Multidimensional GC-MS.

False detection of pesticides in agricultural produce may raise serious questions regarding both consumer safety and trade. High levels of delta-hexachlorocyclohexane (δ-HCH; 11.7-22.3 mg/kg) were detected in some tobacco samples in a retention time-based GC analysis. Hence, the selection of an appropriate analytical method is an uncompromisable necessity. This research work aimed to elucidate false detection of pesticides along with identification of coeluting tobacco matrix compounds to understand the dynamics of false detection with an increase in the number of analyzed pesticides and to screen suitable analytical methods. Initially, retention time-based GC analysis was performed for monitoring of 10 pesticide residues in tobacco leaf matrix, followed by GC-MS/selected-ion monitoring (SIM) analysis. Then, the total number of pesticides to be analyzed was increased to 47, and residue analysis was performed by involving GC-MS/SIM and multidimensional (MD) GC-MS. A false-positive detection of δ-HCH due to a coeluting tobacco aroma compound, neophytadiene, during residue analysis of 10 pesticides in tobacco (Nicotiana tabacum L.) leaf was observed. This problem was resolved by employing the unique quantifier and qualifier ions in SIM mode. However, with 47 pesticides, neophytadiene completely masked the signal of δ-HCH, which resulted in an impure spectrum of δ-HCH (<30% similarity match) even after application of selective quantifier and qualifier ions. Finally, MDGC-MS analysis could resolve it by chromatographic separation of the said analyte from the coeluting matrix compound. The findings of this work offer the potential to minimize false reporting of target pesticides to comply with consumer safety and trade standards. The study identifies various tobacco matrix compounds coeluting with pesticides during multiresidue analysis. Neophytadiene, a tobacco aroma compound, resulted in false-positive detection of δ-HCH. The MDGC-MS could be effectively used as a confirmatory analysis tool for reliable detection of pesticide residue in tobacco leaf matrix.

Application of Automated Mini-Solid-Phase Extraction Cleanup for the Analysis of Pesticides in Complex Spice Matrixes by GC-MS/MS.

Pesticide residues are routinely tested in spices for trade compliance. This results in a huge sample load for food testing laboratories and demands automation in sample preparation. Although there exists a method for the analysis of pesticides in fruits using an automated sample cleanup by mini-solid-phase extraction (mini-SPE) technique, no study is available to date on spices. This study aims to develop an automated sample cleanup method using mini-SPE technique in a range of spices, including chili powder, turmeric, black pepper, cumin, coriander, and cardamom. This automated sample preparation workflow involved an X-Y-Z instrument autosampler, and a set of mini-SPE cartridges comprising cleanup sorbents. Spice samples were extracted by acetonitrile, and the extract was put into an autosampler vial for automated mini-SPE cleanup before analysis by GC tandem MS. For an efficient cleanup, three different sorbent compositions were compared along with various automated workflows. For the relatively simple matrixes (e.g., coriander, cumin, and cardamom), the LOQ for the target pesticides was 10 ng/g with acceptable recovery, and precision. The method provided an LOQ of 10 ng/g for around 77% of the compounds in the relatively complex matrixes (e.g., turmeric, chili powder, and black pepper). The remainder of the compounds had satisfactory recoveries at 20 ng/g and higher levels. Given its time effectiveness and efficient analytical performance, this method can be adopted in commercial food testing laboratories for time-bound analysis of a large volume of samples. The study describes effectiveness of the automated mini-SPE cleanup in multiresidue analysis of pesticides in a range of spice matrixes. The method facilitates high-throughput residue analysis in compliance with the regulatory requirements of sensitivity and method performance.

Апробація методики вимірювання вмісту залишкових кількостей пестицидів у плодах томатів

A pprobation of method was studied, the values which characterizing the suitability of the developed and tested method measuring a pesticides residual content in tomatoes have been established. It is established that the working range of measurement of pesticide residues is from 0.01 mg/kg to 1.0 mg/kg, the error of the test results within the working range does not exceed 10%. Percentage of xenobiotics extracted from samples was established in studies of tomatoes samples artificially enriched with pesticides. The percentage of extraction is in the range of 80% to 110%, the coefficient of variation does not exceed 5%. The stability of the technique is established for 6 months in a series of in-laboratory studies of reference samples. The technique was tested in the analysis of 53 samples of tomato fruits, 5 samples of tomato paste and 10 samples of tomato juice. According to the results of chromatographic control by chromatograms of 47 tomato fruits samples, no xenobiotics were detected, one sample of tomatoes and five samples of tomato paste with trace amounts of target pesticides were detected (azoxystrobin, deltamethrin, dimethomorph, metalaxyl-M, pyraclostrobin) according to the Ukraine and the EU hygiene standards.

A reliable LC-MS/MS-based method for trace level determination of 50 medium to highly polar pesticide residues in sediments and ecological risk assessment.

The occurrence of polar pesticides in sediments has not been extensively investigated because of their relatively poor hydrophobicity and apparently less persistence in the environment. However, their continuous release into the aquatic systems calls for the evaluation of their potential accumulation in sediments and the role of this matrix as a potential source of these compounds. Considering this, a method based on pressurized liquid extraction (PLE), extract clean-up by solid phase extraction (SPE), and analyte determination by liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) was developed and validated to analyze 50 relevant (frequently used and/or regulated or found in water) medium to highly polar pesticides in sediments. The method showed good performance regarding accuracy (relative recoveries between 76 and 124%), precision (relative standard deviation values < 20%), sensitivity (LODs in the low nanogram per gram for most compounds), linearity (coefficients of determination > 0.99), and matrix effects (negligible for all analytes). The use of an isotope dilution approach for quantification ensures result reliability. As a part of the validation process, the method was applied to the analysis of the target pesticides in sediments from the Llobregat River (NE Spain) showing the presence of five of them, namely, terbutryn, dichlorvos, terbuthylazine, diazinon, and irgarol. All 5 pesticides, due to both the concentrations found and their physical-chemical characteristics, demonstrate high potential for bioaccumulation and risk to aquatic organisms. Additional multi-disciplinary studies that investigate pesticide occurrence in different aquatic compartments and evaluate the potential risks for aquatic ecosystems are required to assess the environmental impact and significance of the presence of pesticides in sediments. Graphical Abstract.

Emission estimation and fate modelling of three typical pesticides in Dongjiang River basin, China

Pesticides are widely and intensively used in the world for crops protection. High pesticide loadings can potentially pollute the water resource. However, little is known about the usage, environmental emission and fate of pesticides in river basins. Here, we firstly established a pesticide emission estimation method, and investigated the environmental fate of three commonly used pesticides (chlorpyrifos, triazophos, and isoprothiolane) in Dongjiang River basin, southern China using mathematical modelling approach in combination with field monitoring. The distributed hydrological model SWAT (Soil and Water Assessment Tool) was applied to model the emission of the target pesticides from farmland to stream water, and their fate in the basin. A satisfactory model calibration for flow and suspended sediment was obtained based on eight-year observation data of four hydrological monitoring stations in Dongjiang River basin. The differences between the simulation and observation of pesticides were almost within an order of magnitude, including more than 53% differences within 0.5 order of magnitude. In the river basin, 78860 kg of chlorpyrifos, 54990 kg of triazophos and 35320 kg of isoprothiolane were sprayed onto the crops, the estimated annual emissions of the basin come up to 1801 kg, 3779 kg, and 2330 kg under the conditions of rainfall, surface runoff and percolation. After a series of environmental processes including settlement and degradation within the channels, the predicted export masses for chlorpyrifos, triazophos and isoprothiolane were reduced to 266 kg, 1858 kg, 1350 kg, respectively. Successful prediction suggests that the reliable estimation method combing the SWAT modelling can help us understand the source, concentration levels and fate of pesticides in river basin in different scales. Combing the method of emission and fate modelling method we proposed, countries and regions lacking pesticide-application database can facilitate better management of pesticides.