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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]

An effective analytical method for the simultaneous determination of a novel insecticide flupyradifurone and its two metabolites was developed using ultra high performance liquid chromatography with tandem mass spectrometry coupled with a quick, easy, cheap, effective, rugged, and safe procedure. The three target compounds were extracted with acetonitrile and cleaned up with octadecylsilane, and were separated successfully between 1.9 and 3.1 min using an HSS T3 chromatographic column connected to an electrospray ionization source. All the matrix-matched samples at three fortified levels (0.01, 0.05, and 0.5 mg/kg) provided satisfactory recoveries in the range of 70.3-116.5% with relative standard deviations below 18.6%. The limits of quantitation were 10 μg/kg for flupyradifurone and difluoroethylamino-furanone and 100 μg/kg for 6-chloronicotinic acid. The limit of quantification of flupyradifurone was far below the maximum residue limit in the USA. The method is of great significance for establishing maximum residue limits in China. [ABSTRACT FROM AUTHOR]

A reliable and efficient method was firstly established for the simultaneous determination of saflufenacil and its metabolites (M800H02, M800H11 and M800H35) in cereals (soybean and corn) and fruits (apple, grape and orange), based on a triple quadrupole liquid chromatography mass spectrometer. The four target compounds were extracted with acetonitrile and purified by Florisil or Florisil with octadecylsilane from the cereals and fruits. Determination of the targets was achieved within 3.5 min by using Shim‐pack GIST C18 column connected to an electrospray ionization source (ESI‐ mode). The method showed excellent linearity (R2 > 0.9984), and the limits of quantitation were 1 µg/kg for all compounds. Average recoveries were in the range of 74.6%–108.1%, with an intra‐day relative standard deviation between 0.9% and 18.3%. The inter‐day relative standard deviation was less than 13.8%. The results demonstrate that this method is convenient for monitoring the residues of saflufenacil and its metabolites in food matrices. Practical applications: Saflufenacil controls many common annual broadleaf weed efficiently, it has been developed and launched into the market by domestic enterprises. Consequently, an analysis method for monitoring saflufenacil in food sample will be urgently needed in China over the next few years. This method provides separation with good specificity within 3.5 min, which is less than previous studies. For the five matrixes, the method presented satisfactory validation parameters in terms of good linearity, low limit of quantitations, and satisfactory accuracy and precision. Therefore, the method established in this study is a valuable tool to overcome gaps in determining saflufenacil and its metabolites in cereals and fruits, in order to accurate evaluation of risk and ensure food safety. [ABSTRACT FROM AUTHOR]

In this study, a modified quick, easy, cheap, effective, rugged, and safe (QuEChERS) method was used for the simultaneous determination of thifluzamide and difenoconazole in grapes by ultra-high-performance liquid chromatography coupled with tandem mass spectrometry (UHPLC-MS/MS) using a Waters Acquity UHPLC BEH C18 column. To compare the effects of different sorbents for thifluzamide and difenoconazole in grapes, samples were extracted with acetonitrile and cleaned up using five different types of sorbents at the same concentration level (0.1 mg/kg). The method was validated at three fortification concentrations (0.05, 0.1, 0.5 mg/kg) with five replicates in each matrix using 40 mg of primary secondary amine (PSA) + 10 mg of graphitised carbon black (GCB) as clean-up sorbents. The recoveries were between 76.3 and 109.3%, and the RSDr (intra-day precision, n = 5) and RSDR (inter-day precision, n = 15) values ranged from 3.5 to 8.1% and 5.8 to 22.2%, respectively. The limits of quantification (LOQ) for thifluzamide and difenoconazole were 0.07 and 0.04 mg/kg, respectively. The method showed excellent linearity and reliability. The results demonstrated that the method was effective in detecting the two compounds. In this study, we also investigated the dissipation behaviours of thifluzamide and difenoconazole in grapes. The dissipations of thifluzamide and difenoconazole followed the first-order kinetics with the half-lives of 3.9-16.3 days. [ABSTRACT FROM AUTHOR]

Abstract: The dissipations of afidopyropen and its metabolite in wheat plant and soil were determined using a quick, easy, cheap, effective, rugged, and safe method with ultra‐high performance liquid chromatography and tandem mass spectrometry under a field ecosystem. The limits of quantification were estimated for both target compounds as 0.001 mg/kg. The recoveries of afidopyropen and its metabolite ranged from 94 to 114% (soil), 90 to 109% (wheat seed) and 81 to 91% (wheat straw) at levels of 0.001, 0.01, 0.1, and 2.0 mg/kg with relative standard deviations ≤7%. The results of the residual dynamics experiments showed that afidopyropen dissipated rapidly in wheat plant and soil. Its metabolite initially showed a tendency of rapid increase followed by a decrease in wheat plant but could not be detected in soil. The data showed that the first + first‐order model was more suitable for describing the decline of afidopyropen in wheat and soil. The half‐lives of afidopyropen in wheat plant and soil were 1.65 and 1.21 days, respectively. [ABSTRACT FROM AUTHOR]