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A sensitive extraction and instrumental method was established to detect topramezone and its metabolite (M670H05) in maize and animal-origin foods. Two years of field experiments were carried out to study the dissipation dynamics of topramezone in maize straw, and their residue levels of actual samples collected from the supermarket were determined. They were extracted using liquid–liquid extraction (LLE), and ultra-high-performance liquid chromatography–tandem mass spectrometry was used for detection. The limit of quantification was 0.005 mg kg−1. Recoveries ranged between 73.8% and 109.9% at 3 spiking levels with intraday relative standard deviation (RSD) ≤17.7% and the inter-day ≤18.1%, which meets the requirements of SANTE/12682/2019. Dissipation dynamics experiment showed that, the deposition of topramezone in maize straw in Jilin were <0.005–0.62 mg kg−1with 28 days after application. And the residue level of market samples were all less than 0.005 mg kg−1, much lower than the MRLs (range from 0.01 to 0.8 mg kg−1) set by European Union, United States Food and Drug Administration, China, and Canada. This method was effective to analyse the residues of topramezone and M670H05. [ABSTRACT FROM AUTHOR]

A rapid and sensitive ultra-high-performance liquid chromatography-tandem mass spectrometry method, in conjunction with multiwalled carbon nanotube purification, was developed to determine the mefentrifluconazole levels in grapes, cucumbers, tomatoes, peppers, wheat, maize, eggs, milk, pork, chicken, and fish. After purification, tandem mass spectrometry of mefentrifluconazole required <3.0 min. Matrix-matched external standard curves were used to quantify the residual mefentrifluconazole. The method meets the requirements of the European Union Document SANTE/11813/2017. Quantification was linear between 5 and 500 μg/kg (R2 ≥ 0.9988), and both the intra- and interday relative standard deviations were ≤13.7%. Analyte recovery ranged from 81.5% to 107.6%. The limit of mefentrifluconazole quantification was 5 μg/kg for all matrices. The method successfully detected and quantified mefentrifluconazole that had been applied to cucumbers and tomatoes grown in a test field. These results imply that the proposed method is effective and reliable for detecting mefentrifluconazole residues in plant- and animal-derived foods. [ABSTRACT FROM AUTHOR]

Abstract: An ultra high‐performance liquid chromatography with tandem triple quadrupole mass spectrometry residue method was developed and validated for the quantification and identification of dinotefuran and its main metabolites 1‐methyl‐3‐(tetrahydro‐3‐furylmethyl) urea and 1‐methyl‐3‐(tetrahydro‐3‐furylmethyl) guanidine in fruit (watermelon), vegetable (cucumber), cereal (rice), animal‐derived foods (milk, egg, and pork), soil, and water. The samples were extracted with acetonitrile containing 15% v/v acetic acid and purified with dispersive solid‐phase extraction with octadecylsilane, primary secondary amine, graphitized carbon black, or zirconia‐coated silica prior to analysis. The method had an excellent linearity (R2 ≥ 0.9942, 1–500 μg/L) and satisfactory recoveries (73–102%) at five spiked levels (0.001, 0.01, 0.05, 0.5, and 2 mg/kg) with intra‐ or interday precision in the range of 0.8–9.5% and 3.0–12.8% for the three compounds in the eight matrices. The limits of quantification were 10 μg/kg for 1‐methyl‐3‐(tetrahydro‐3‐furylmethyl) guanidine and 1 μg/kg for 1‐methyl‐3‐(tetrahydro‐3‐furylmethyl) urea and dinotefuran. The applicability of the developed method was demonstrated by determining the occurrence of dinotefuran, 1‐methyl‐3‐(tetrahydro‐3‐furylmethyl) guanidine, and 1‐methyl‐3‐(tetrahydro‐3‐furylmethyl) urea in various samples from plants, animal‐derived foods, and the environment. From 80 samples, 70 contained dinotefuran (0.8–11.7 μg/kg), among which six also contained 1‐methyl‐3‐(tetrahydro‐3‐furylmethyl) urea (water and rice, 0.5–0.9 μg/kg). [ABSTRACT FROM AUTHOR]

The new triketone herbicide, tembotrione, provides excellent weed control in corn fields. To evaluate its safety, we established a modified QuEChERSpretreatment and ultra-high performance liquid chromatography-mass spectrometry method, using acetonitrile with 2% formic acid as the extractant and C18 as absorbent. The dissipation dynamics of tembotrionein corn straw and the terminal residual levels in all three corn matrices were studied in Henan and Jilin provinces. The linearity was excellent in the range of 0.01 to1 mg L−1, with the determination coefficient (R2) ≥0.9954. The average recovery was between 74% and 117%, with intra-day relative standard deviation less than 18.9 and the inter-day relative standard deviation less than 17.5. The degradation dynamic experiment showed that tembotrione decreased over time and followed the first-order kinetic equation. Our results showed that the regression coefficients of the dynamic equations were 0.9906 and 0.9897, with half-lives of 0.7 and 0.8 d, respectively. The final residue results showed that the maximum residues of tembotrione detected in corn in Jilin and Henan were 0.041 and 0.051 mg kg−1, respectively. The risk quotient (RQ) were calculated as 0.186 and 0.246, both of which were less than 1, which indicated an acceptable risk. [ABSTRACT FROM AUTHOR]

Highlights: [•] QuEChERS method was firstly used to extract oxathiapiprolin and its 2 metabolites. [•] UPLC–MS/MS was firstly used to determine oxathiapiprolin and its 2 metabolites. [•] Various solvents and sorbents were evaluated for the sample preparation. [•] The method exhibits acceptable recovery and high sensitivity. [•] Application of method validation showed good results. [ABSTRACT FROM AUTHOR]

The effects of spraying and root irrigation on the uptake and transport of the fungicide difenoconazole under hydroponic and soil cultivation were investigated. Rice was used as the crop for a short-term exposure experiment. A modified QuEChERS pre-treatment combined with ultra-high-performance liquid chromatography–tandem mass spectrometry was used to extract and detect difenoconazole from rice plants, water and soil. The recoveries of difenoconazole were in the range of 72.8–110.5%, with a relative standard deviation of 2.4–19.5% for all the samples when spiked with 0.01, 0.1 and 1 mg kg−1 of difenoconazole, respectively. The limit of quantitation (LOQ) of this method was 0.01 mg kg−1. The exposure results showed that difenoconazole could be absorbed by rice plants and transmitted to different parts of rice plants in all the treatments. In the hydroponic experiment, difenoconazole was mainly distributed in the roots of rice regardless of whether irrigation or spraying was used. For rice cultivated in soil, difenoconazole mainly accumulated in leaves after the root irrigation treatment, whereas after the spraying treatment, the rice roots were the main site of accumulation of difenoconazole. This experiment extends our knowledge of the influence of the cultivation system and application mode on the translocation of difenoconazole in rice plants. [ABSTRACT FROM AUTHOR]

Famoxadone is a widely used chiral fungicide on tomato, apple, and grape. But it is still being employed as a racemic mixture without distinguishing the difference between enantiomers, which often leads to its inaccurate risk assessment. In this study, a rapid, sensitive, and reliable chiral analytical method was developed for famoxadone enantiomers by ultra high performance liquid chromatography/tandem mass spectrometry, optimal separation condition was achieved with Lux Amylose‐1 column using acetonitrile/water (70:30, v/v) as mobile phase at 0.3 mL/min in 6 min. The average recoveries for two enantiomers in all of the matrices at three spiking levels ranged from 89.8 to 109.4%, with relative standard deviation less than 9.5%. The limits of quantification for all enantiomers in tomato, apple, and grape were not more than 4 μg/kg. And the proposed method was successfully applied to investigate the enantioselective degradation of famoxadone enantiomers in tomato, apple, and grape. The data showed that S‐(+)‐famoxadone was preferentially degraded comparing to the R‐(−)‐famoxadone in tomato, apple, and grape. The potential reasons of the enantioselective behavior were also discussed. This study could help in better understanding the environmental fate of famoxadone and the rational use of chiral pesticide in agricultural production. [ABSTRACT FROM AUTHOR]

The analysis of pesticide residues in aquatic products is challenging due to low residue levels and the complex matrix interference. In this study, we developed a simple, fast method for the trace analysis of 90 pesticides and metabolites in aquatic products. The analytes covered a wide polarity range with log Kow (log octanol-water partition coefficient) ranging from −1.2 to 6.37. Grass carp (Ctenopharyngodon idellus) and prawn (Penaeus chinensis) samples were chosen to validate the quantification method. The samples were extracted by 0.2% formic-acetonitrile, cleaned by solid-phase extraction (PRiME HLB), and analyzed by high performance liquid chromatography−tandem mass spectrometry. The results showed good linearities for the analytes and were observed in the range of 0.05–50 μg/L. The recoveries of the method were within 50.4–118.6%, with the relative standard deviations being lower than 20%. The limits of quantifications (LOQs) of the method were in the range of 0.05–5.0 μg/kg, which were superior to values compared with other research. The developed method was applied to detect pesticide residues in prawn samples from eastern coastal areas of China. Three herbicide residues of diuron, prometryn, and atrazine were detected in prawn samples. The method was sensitive and efficient, which is of significance in expanding the screening scope and improving the quantitative analysis efficiency in aquatic products. [ABSTRACT FROM AUTHOR]

Imidacloprid (IMI), the most commonly used neonicotinoid, is widely present in both the environment and agro-products due to extensive and prolonged application, posing potential risks to ecological security and human health. This study introduced a sensitive and rapid fluorescence-linked immunosorbent assay, employing Quantum Dot-Streptavidin conjugate (QDs-SA-FLISA), for efficient monitoring of IMI residues in agro-products. Under optimized conditions, the QDs-SA-FLISA exhibited a half-maximal inhibition concentration (IC 50) of 1.70 ng/mL and a limit of detection (LOD, IC 20) of 0.5 ng/mL. Investigation into the sensitivity enhancement effect of the QDs-SA revealed that the sensitivity (IC 50) of the QDs-SA-FLISA was 7.3 times higher than that of ELISA. The recoveries and relative standard deviation (RSD) ranged from 81.7 to 118.1 % and 0.5–9.4 %, respectively, for IMI in brown rice, tomato and pear. There was no significant difference in IMI residues obtained between QDs-SA-FLISA and UHPLC-MS/MS. Thus, the QDs-SA-FLISA represents a reliable approach for the quantitative determination of IMI in agro-products. [Display omitted] • A FLISA based on Quantum Dot-Streptavidin was developed to detect imidacloprid. • QDs-SA-FLISA exhibited higher sensitivity compared to the conventional ELISA. • Three kinds of matrices were studied by spiked recovery experiment. • QDs-SA-FLISA was successfully applied to real samples and verified by UHPLC-MS/MS. [ABSTRACT FROM AUTHOR]

The Soybean (Glycine max (L.) Merr.) is a kind of oilseed crop and also a good source of nutrition for human beings, poultry and other animals. Clomazone and acetochlor are two kinds of pesticides of great concern that are widely used to protect soybean from weeds. The purpose of this study was to evaluate the food safety of soybean after applying clomazone and acetochlor. For this purpose, the contents of clomazone and acetochlor in green soybean, green straw, mature soybean, and mature straw collected from six locations in different provinces of China were determined by ultra-high performance liquid chromatography coupled with tandem mass spectrometry (UPLC-MS/MS). The recoveries of the compounds at different concentration levels were 86%-110% while the relative standard deviations (RSDs) ranged from 2% to 31 11%. The limits of quantification (LOQs) for each matrix of the two herbicides were 0.01 mg/kg. Residues of clomazone and acetochlor in soybean at harvest time were all below 0.01 mg/kg at the recommended dosage. [ABSTRACT FROM AUTHOR]

In this study, an effective and sensitive chiral analytical method was developed to detect zoxamide enantiomers in vegetables, fruits and environmental matrices using ultra-high-performance liquid chromatography-tandem mass spectrometry. Optimal separation conditions were achieved with Lux Amylose-2 chiral column using acetonitrile/water (70:30 v / v ) as mobile phase with a flow rate and column temperature of 0.5 mL/min and 25 °C. The absolute configuration, optical rotation and elution order were confirmed for the first time. The average recoveries in all matrices at four spiking levels (0.5, 5, 50, 250 μg/kg) ranged from 89.7 to 117.4%, with relative standard deviations being less than 10.9% for two enantiomers. The enantioselective dissipation of zoxamide in tomato showed that (−)- R -zoxamide was preferentially degraded leading to an enrichment of (+)- S -isomer, with half-lives of 3.80 d and 5.17 d, respectively. Inversely, (+)- S -zoxamide degraded faster than (−)- R -zoxamide in pepper (1.95 day and 2.28 day, respectively) and grape (2.03 day and 2.87 day). No significant enantioselectivity was observed in cucumber. The results of this study could help facilitate more accurate risk assessments of zoxamide in the future. [ABSTRACT FROM AUTHOR]

In this study, a rapid and sensitive method was developed for determining fenamidone and propamocarb hydrochloride residues in vegetables and soil by ultra-performance liquid chromatography-tandem mass spectrometry. The dissipation dynamics of fenamidone and propamocarb hydrochloride in pepper and soil was investigated in Beijing, Henan and Shandong provinces. The target compounds were extracted with methanol and cleaned with dispersive solid phase extraction using primary secondary amine. Two pairs of precursor product ion transitions for fenamidone and propamocarb hydrochloride were measured and evaluated. Average recoveries of fenamidone in potato, tomato, cabbage, pepper and soil at three levels (10, 100 and 1000 μg kg−1) ranged from 76.91% to 107.31% with relative standard deviations (RSDs) from 2.74% to 10.87% (n = 15). The average recoveries of propamocarb hydrochloride ranged from 74.84% to 97.96% with RSDs from 2.43% to 16.16% (n = 15). The limits of detection (LODs) for fenamidone in each matrix were 0.131–0.291 μg kg−1, and the limits of quantification (LOQs) were 0.436–0.970 μg kg−1. The LODs for propamocarb hydrochloride were 0.125–0.633 μg kg−1, and the LOQs were 0.417–2.11 μg kg−1. The results also showed that the dissipation of fenamidone and propamocarb hydrochloride in pepper and soil followed first-order kinetics model more than that of bi-exponential models. The half-lives of propamocarb hydrochloride were 6.90–15.78 days in pepper and 13.56–23.02 days in soil. The half-lives of fenamidone were 7.48–11.29 days in pepper and 35.18–42.78 days in soil. [ABSTRACT FROM AUTHOR]

The present study attempts to investigate a rapid, effective and sensitive analytical method to determine a new fungicide penflufen and its metabolite residues in potato, cowpea, corn, wheat and rice using ultra-performance liquid chromatography coupled with tandem mass spectrometry (UHPLC–MS/MS). The compounds were extracted using acetonitrile and cleaned up by primary secondary amine (PSA) and octadecylsilane (C18). Both compounds were determined in less than 5.0 min using an electrospray ionization source in positive mode (ESI+). The calculated limits of detection and quantification were below 0.018 μg kg −1 and 0.060 μg kg −1 in different matrices. The method revealed excellent linearity (R 2 > 0.9957) for both compounds. The recoveries ranged from 76.1 to 101.0% for both compounds with RSD values lower than 9.8% in all matrices. The results demonstrated that the method is reliable and effective enough for the routine detecting penflufen and its metabolite residues in vegetables and cereals. [ABSTRACT FROM AUTHOR]

A sensitive and effective method for the simultaneous determination of residues from a new fungicide, oxathiapiprolin, and its metabolites (IN-E8S72 and IN-WR791) in soil, water, and sediment, was developed using ultra high performance liquid chromatography with tandem mass spectrometry. Three compounds were extracted from water, soil, and sediment by using acetonitrile and different proportions of formic acid aqueous solution (1% v/v for water; 2% v/v for soil; and sediment), and were cleaned with octadecylsilane. The target compounds were determined within 5 min using an electrospray ionization source in the positive mode for oxathiapiprolin and in the negative mode for the two metabolites. The limits of quantification for all the three compounds were 0.1 µg/kg in water and 1 µg/kg in soil and sediment. Recovery studies were performed using three spiked levels (0.1, 1, and 10 µg/kg for water; 1, 10, and 50 µg/kg for soil and sediment). The overall average recoveries ranged from 64.8 to 112.7% with all intra- and interday relative standard deviation values below 19.4 and 19.1%, respectively. The method validation confirmed that the proposed method was convenient and reliable for determining residual oxathiapiprolin and its metabolites in soil, water, and sediments. [ABSTRACT FROM AUTHOR]

Difenoconazole is a widely used triazole fungicide that has been frequently detected in the environment, but comprehensive study about its environmental fate and toxicity of potential transformation products (TPs) is still lacking. Here, laboratory experiments were conducted to investigate the degradation kinetics, pathways, and toxicity of transformation products of difenoconazole. 12, 4 and 4 TPs generated by photolysis, hydrolysis and soil degradation were identified via UHPLC-QTOF/MS and the UNIFI software. Four intermediates TP295, TP295A, TP354A and TP387A reported for the first time were confirmed by purchase or synthesis of their standards, and they were further quantified using UHPLC-MS/MS in all tested samples. The main transformation reactions observed for difenoconazole were oxidation, dechlorination and hydroxylation in the environment. ECOSAR prediction and laboratory tests showed that the acute toxicities of four novel TPs on Brachydanio rerio , Daphnia magna and Selenastrum capricornutum are substantially lower than that of difenoconazole, while all the TPs except for TP277C were predicted chronically very toxic to fish, which may pose a potential threat to aquatic ecosystems. The results are important for elucidating the environmental fate of difenoconazole and assessing the environmental risks, and further provide guidance for scientific and reasonable use. [Display omitted] • Difenoconazole degrade faster under neutral or alkaline solutions and is stable in soils. • Four new transformation products were identified and confirmed by standards. • Transformation products are produced by oxidation, dechlorination and hydroxylation. • The degradation of difenoconazole reduces its toxicity to aquatic organisms. • Eleven phototransformation products could still be toxic to aquatic life. [ABSTRACT FROM AUTHOR]