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In this study, an efficient and fast method for the determination of the herbicide mesotrione and its two metabolites [4-methylsulfonyl-2-nitrobenzoic acid (MNBA) and 2-amino-4-methylsulfonylbenzoic acid (AMBA)] in rice, rice plants, rice hulls, water, and soil was developed, using ultra performance liquid chromatography coupled with tandem quadrupole (Xevo TQ-S) mass spectrometry (UPLC-Xevo TQ-S-MS/MS). The recoveries of the compounds were 68.6%–108.4% at different levels. The intra-day relative standard deviation (RSD) ranged from 2.0% to 14.4%, and the inter-day RSD, from 1.9% to 11.4%. The limits of quantification (LOQ) were ranged from 0.146 to 4.545 μg kg −1 for mesotrione, MNBA and AMBA. Dissipation and residual assays with the commercial formulation were conducted at three locations. The dissipation rates of the compounds were fast in rice plants, soil, and water, and residues at harvest were not detected in any of the three localities. [ABSTRACT FROM AUTHOR]

[Display omitted] • The absolute configuration of fluindapyr enantiomers was first confirmed. • SFC-MS/MS was initially developed for detection of fluindapyr enantiomers. • Enantioselective behaviors of fluindapyr in different organs and plants were various. Fluindapyr is a pyrazolamide chiral fungicide of succinate dehydrogenase inhibitor (SDHIs) with two enantiomers. Pesticide enantiomers often exhibit different biological activities, toxicity due to their different enantioselectivity. Therefore, it is important to separate fluindapyr enantiomers and assess each enantiomer. In this study, fluindapyr enantiomers were baseline separated by supercritical fluid chromatography-mass spectrometry in 2 min. The limit of quantification (LOQ) of this method was 5 μg/kg. The developed method was applied to monitor the fluindapyr enantiomers in cucumber and tomato, the data showed that R- (-)-fluindapyr was preferentially degraded in tomato leaves, S -(+)-fluindapyr was preferentially degraded in cucumber leaves, and fluindapyr enantiomers had no enantioselective degradation behavior in two fruits. It is proved again that enantiomers have different enantioselective degradation behavior with the different plant species and even to different parts of the same plant. The enantioselectivity is likely to be caused by different biodegradation enzyme systems. [ABSTRACT FROM AUTHOR]

• SFC-MS/MS was initially developed for detection of mefentrifluconazole enantiomers. • Enantioselective behaviors of mefentrifluconazole were evaluated in the greenhouse vegetables system and pickling process. • S -(+)-mefentrifluconazole was preferentially degraded than R -(−)-mefentrifluconazole in pepper and pickling cucumber. • Mefentrifluconazole were removed 89.2% in cucumber, and 30.8% in pepper after cleaning and pickling. A fast, effective, and environmental-friendly method was developed for enantioseparation and analysis of mefentrifluconazole in vegetables based on supercritical fluid chromatography tandem mass spectrometry. The enantioselective behaviors of mefentrifluconazole enantiomers in tomato, cucumber, and pepper in the greenhouse, and pickled cucumber and pepper during processing were investigated. Mefentrifluconazole enantiomers could obtain baseline separation within 2 min. The average recoveries of all matrices ranged from 78.4% to 119.0%, with relative standard deviations less than 16.8% for two enantiomers. S -(+)-mefentrifluconazole was preferentially degraded in pepper, while there was no enantioselectivity in tomato and cucumber under field conditions. During processing, S -(+)-mefentrifluconazole was reduced preferentially than R -(−)-mefentrifluconazole in pickled cucumber and cucumber brine. Inversely, R -(−)-mefentrifluconazole degraded faster than S -(+)-mefentrifluconazole in pepper brine. But, no obvious enantioselectivity was observed in pickled pepper. The result of this study could contribute to a more accurate dietary risk assessment of mefentrifluconazole in vegetables and processed products. [ABSTRACT FROM AUTHOR]