Department of Applied Chemistry, China Agricultural University, Beijing, China.
Chirality. 2014 Mar;26(3):155-9. doi: 10.1002/chir.22284. Epub 2014 Feb 4.
Vinclozolin is a chiral fungicide with potential environmental problems. The chiral separation of the enantiomers and enantioselective degradation in soil were investigated in this work. The enantiomers were separated by high-performance liquid chromatography (HPLC) on Chiralpak IA, IB, and AZ-H chiral columns under normal phase and the influence of the mobile phase composition on the separation was also studied. Complete resolutions were obtained on all three chiral columns under optimized conditions with the same elution order of (+)/(-). The residual analysis of the enantiomers in soil was conducted using accelerate solvent extraction followed by HPLC determination. The recoveries of the enantiomers ranged from 85.7-105.7% with relative standard deviation (SD) of 0.12-3.83%, and the limit of detection (LOD) of the method was 0.013 µg/g. The results showed that the degradations of vinclozolin enantiomers in the soils followed first-order kinetics. Preferential degradation of the (-)-enantiomer was observed only in one soil with the largest |ES| value of 0.047, and no obvious enantioselective degradation was observed in other soils. It was found that the persistence of vinclozolin in soil was related to pH values based on the half-lives. The two enantiomers disappeared about 8 times faster in basic soils than that in neutral or acidic soils.
烯菌唑是一种具有潜在环境问题的手性杀菌剂。本工作研究了其对映异构体的手性分离和在土壤中的对映选择性降解。采用正相高效液相色谱法（HPLC），在 Chiralpak IA、IB 和 AZ-H 手性柱上，对手性农药烯菌唑对映体进行了拆分，并研究了流动相组成对分离的影响。在优化条件下，三种手性柱都能得到完全分离，对映体的洗脱顺序相同。采用加速溶剂萃取（ASE）和高效液相色谱（HPLC）联用的方法对土壤中的对映体残留进行了分析。该方法对映体的回收率在 85.7-105.7%之间，相对标准偏差（RSD）在 0.12-3.83%之间，方法的检出限（LOD）为 0.013μg/g。结果表明，在土壤中，烯菌唑对映体的降解符合一级动力学。在一种土壤中仅观察到（-）-对映体的优先降解，且最大的对映体选择性参数（ES）值为 0.047，而在其他土壤中未观察到明显的对映体选择性降解。基于半衰期，发现烯菌唑在土壤中的持久性与 pH 值有关。两种对映体在碱性土壤中的消失速度比在中性或酸性土壤中快约 8 倍。
