Li Shaotong, Li Zhaoyang, Li Qiaoling, Zhao Jiahe, Li Sen
College of Bioscience and Bioengineering, Hebei University of Science and Technology, Shijiazhuang, Hebei Province, China.
College of Science, Hebei University of Science and Technology, Shijiazhuang, Hebei Province, China.
Chirality. 2016 Jan;28(1):72-7. doi: 10.1002/chir.22544. Epub 2015 Oct 26.
Permethrin (PM), cypermethrin (CP), and cyfluthrin (CF) are three important synthetic pyrethroids, which contain two, four, and four enantiomeric pairs (diastereomers) and thus have four, eight, and eight stereoisomers, respectively. In this study, the stereo- and enantioselective degradation of PM, CP, and CF in a Shijiazhuang alkaline yellow soil and a Wuhan acidic red soil were studied in detail by a combination of achiral and chiral high-performance liquid chromatography (HPLC). The results showed that PM, CP, and CF degraded faster in Shijiazhuang soil than in Wuhan soil, and the dissipation rate followed an order of PM > CF > CP in both soils. The three pyrethroids exhibited similar diastereomer selectivity, while CP and CF showed higher enantioselectivity than PM. Moreover, the trans-diastereomers degraded faster, and showed higher enantioselectivity than the corresponding cis-diastereomers. For PM, the enantiomer 1S-trans-PM degraded most rapidly in both soils. As for CP and CF, the highest enantioselectivity was observed for diastereomer trans-3, and the insecticidally active enantiomer 1R-trans-αS degraded fastest among the 8 CP or CF stereoisomers in both soils. In addition, the Wuhan acidic soil displayed higher diastereomer and enantiomer selectivity than the Shijiazhuang alkaline soil for the three pyrethroids. Further incubation of CF in an alkaline-treated Wuhan soil showed that the dissipation rate greatly increased and the diastereo- and enantioselectivity significantly decreased after the alkaline treatment process.
氯菊酯（PM）、氯氰菊酯（CP）和氟氯氰菊酯（CF）是三种重要的合成拟除虫菊酯，它们分别含有两对、四对和四对对映体对（非对映异构体），因此分别具有四种、八种和八种立体异构体。在本研究中，采用非手性和手性高效液相色谱（HPLC）联用的方法，详细研究了PM、CP和CF在石家庄碱性黄壤和武汉酸性红壤中的立体选择性和对映体选择性降解。结果表明，PM、CP和CF在石家庄土壤中的降解速度比在武汉土壤中快，且在两种土壤中的消散速率均遵循PM＞CF＞CP的顺序。这三种拟除虫菊酯表现出相似的非对映体选择性，而CP和CF的对映体选择性高于PM。此外，反式非对映异构体降解更快，且比对映的顺式非对映异构体表现出更高的对映体选择性。对于PM，对映体1S-反式-PM在两种土壤中降解最快。至于CP和CF，非对映体反式-3的对映体选择性最高，且在两种土壤中，杀虫活性对映体1R-反式-αS在8种CP或CF立体异构体中降解最快。此外，对于这三种拟除虫菊酯，武汉酸性土壤比石家庄碱性土壤表现出更高的非对映体和对映体选择性。在经过碱性处理的武汉土壤中对CF进行进一步孵育，结果表明，碱性处理后，CF的消散速率大大增加，非对映体和对映体选择性显著降低。
