Paclobutrazol (PBZ) is a kind of chiral pesticide, which is a plant growth regulator and has fungicidal activity. Because of the steric-hindrance effect, there are two enantiomers (2S, 3S; 2R, 3R) in the production. This research studied on the dissipation behavior of chiral pesticide PBZ in the brine during the Chinese cabbage pickled process by phase column-high performance liquid chromatography (HPLC). The result demonstrated the PBZ enantiomers had the different dissipation in the brine. The study on the behavior of chiral pesticide PBZ in food may provide more sufficient data and information for understanding the potential risk in food and evaluating the environmental pollution at the enantiomer level.

Enantiomers of chiral molecules can undergo interconversion leading to markedly different toxicities, which can introduce significant uncertainty when evaluating biological and environmental fates. However, enantiomerization (the reversible conversion of one enantiomer into the other) related to soil microorganism is rarely understood. For better understanding, S-triadimefon and R-triadimefon enantiopure were incubated in different soils with different pH value. Both high-performance liquid chromatography and high-throughput sequencing technology were used to explore target analytes quantitatively and microbial taxa related to the conversion process. Results revealed a significant enantiomerization among the soils. The alkaline soil from Beijing had a faster conversion than neutral soil from Changchun, while acidic soil from Wuhan had no conversion. At the same results, analysis of bacteria community showed higher abundance of Arthrobacter and Halomonas genus in alkaline soil than neutral soil after treatments, but the acidic soil was lower. Moreover, Arthrobacter and Halomonas were responsible for converting S-triadimefon to R-triadimefon and R-triadimefon to S-triadimefon in alkaline and neutral soil, respectively. Thus, these genera may be one of the reasons to explain the enantiomerization in different soils observed in this study. Thus, research at microbial level is necessary for efficient ecological risk assessment of chiral fungicide.

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A novel, rapid and efficient manual shaking and ultrasound-assisted surfactant-enhanced emulsification microextraction (M-UASEME) combined with gas chromatography-flame photometric detection (GC-FPD) was developed for the extraction and determination of eight organophosphorus pesticides (OPPs) in tap water and honey samples. The main parameters that affected the extraction efficiency were investigated and optimized. Under the optimum conditions, the relative standard deviation (RSD, n = 6) ranged from 2.4 to 9.3%. Limits of detection (LOD) were varied between 0.005 and 0.05 µg L for all analytes with the correlation coefficients (r) > 0.9964. Finally, the developed method was successfully applied to determine the eight pesticide residues in real samples. The recoveries of the target analytes in samples were between 82.4 and 96.7%.