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Studies on the differences between chiral pesticide enantiomers have caused widespread concern in the last decade. In the current work, the selective behaviors and different biological activities of paclobutrazol enantiomers during Chinese cabbage pickling process were evaluated. Results of degradation kinetics indicated that when paclobutrazol reside in raw material (Chinese cabbage) and was introduced into the pickling process, the degradation rates of the two paclobutrazol enantiomers were significantly different, the half‐lives of (2R, 3R)‐paclobutrazol (R‐paclobutrazol) and (2S, 3S)‐paclobutrazol (S‐paclobutrazol) were 18.24 and 6.19 d, respectively. Besides, the conversion between the two enantiomers could also be observed, and the conversion rate of R‐paclobutrazol to S‐paclobutrazol was slower than that of reverse process. In addition, from the analysis of 16S rRNA and ITS sequencing, we inferred that the degradation of paclobutrazol was probably due to the presence of Pseudomonas and Serratia. Moreover, there has a significant difference in biological activity between R‐paclobutrazol and S‐paclobutrazol and shown an obviously enantiomeric effects on microbial community composition of pickling system. Besides, the analysis of microbial community displayed R‐paclobutrazol might inhibit the growth of Erwinia (a sort of plant pathogens). Results from this study served to enhance our understanding of chiral pesticide residues on food safety and the potential risks to human health. [ABSTRACT FROM AUTHOR]

[Display omitted] • Magnetic core–shell Fe 3 O 4 @DUT-5 was prepared as MSPE adsorbent. • The method delivered low LOD, good recoveries and satisfactory precision. • Fe 3 O 4 @DUT-5-MSPE-HPLC method proved to be effective and economical. A sample pre-treatment technology, based on magnetic MOF composite Fe 3 O 4 @DUT-5 as the adsorbent, combined with high performance liquid chromatography (HPLC) has been developed and used for the trace analysis of azole fungicide residues in fruits and vegetables. Characterization analysis shows that Fe 3 O 4 @DUT-5 has good stability and excellent saturation magnetism. Under the optimal conditions, the satisfactory enrichment factors (69.6–96.4), and good linearity (10–1000 μg L-1) could be achieved, as well as the low limits of detection (0.054 to 0.313 μg L-1) were proved to be below the maximum residue limits (MRLs) of azole fungicides in agricultural products (10.0 μg kg−1). Additionally, the proposed method has been successfully applied to the determination of target analytes in six fruits and vegetables. The achieved recovery (62.3–100.8%) and reproducibility (lower than 6.4%) meet the requirements of pesticide residue analysis. Moreover, the high adsorption capacity and stability remain unchanged after 5 cycles. And it has a strong saturation magnetization value, which provides a strong guarantee for recycling. As a novel adsorbent, Fe 3 O 4 @DUT-5 showed great potential in the extraction of pesticide residues in fruits and vegetables. [ABSTRACT FROM AUTHOR]

[Display omitted] • Magnetic cyclodextrin polymers were synthesized and used as an adsorbent. • A modified method for the analysis of azole pesticides in medicinal plants. • The proposed method was proved to be simple, rapid, and economical. In this work, a sensitive and cost-effective method for the quantitative analysis of azole pesticides residues in six medicinal plants was established based on magnetic cyclodextrin crosslinked with tetrafluoroterephthalonitrile (Fe 3 O 4 @TFN-CDPs) coupled with high-performance liquid chromatography (HPLC). Through characterization analysis, the outer shell of Fe 3 O 4 @TFN-CDPs has observed coating with a network of the polymer and forming a core–shell structure. Under the optimum conditions, the limits of detection (LODs) and limits of qualification (LOQs) of target pesticides were ranged from 0.011 to 0.106 µg Kg−1 and from 0.036 to 0.354 µg Kg−1, respectively. Finally, the achieved recoveries of pesticides in six medicinal samples fluctuated from 60.1% to 102.3%. Altogether, this method based on Fe 3 O 4 @TFN-CDPs composites provided a new idea for the analysis of trace pesticides in complicated matrices. [ABSTRACT FROM AUTHOR]