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首页> 外文期刊>Journal of Agricultural and Food Chemistry >Chiral stability of synthetic pyrethrold insecticides
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Chiral stability of synthetic pyrethrold insecticides

机译：拟除虫菊酯类农药的手性稳定性

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摘要

Synthetic pyrethroids are chiral compounds consisting of multiple stereoisomers. Evaluation of enantioselectivity in environmental fate and ecotoxicity requires analytical methods that preserve stereoisomer integrity during analysis. In this study, we characterized the stability of stereoisomers from four commonly used pyrethroids, cis-bifenthrin (cis-BF), permethrin (PM), cypermethrin (CP), and cyfluthrin (CF), during gas chromatography (GC) analysis and sample preparation. Stereoisomers of cis-BF and PM were found to be stable, but those of CP and CIF were unstable, under heat or in water. Isomer conversion occurred only at the aC in CIP or CF, causing the analyte stereoisomer to convert to an epimer. At a GC inlet temperature of 260 ° C, about 9% conversion occurred for CIP and CF. In organic solvents and sterile water, stereoisomers of cis-BF and PM were stable, but slow isomer conversion was observed for CP and CF in water at ambient temperature. However, isomer conversion for CP and CF was relatively insignificant (2-3%) when the GC inlet temperature was kept at ≤ 180 ° C or when on-column injection was used. Isomer conversion at the α C in water suggests that abiotic processes may also contribute to enantioselectivity observed in the environment for pyrethroids with the asymmetric α C.
机译：合成拟除虫菊酯是由多种立体异构体组成的手性化合物。对环境命运和生态毒性中对映选择性的评估需要在分析过程中保留立体异构体完整性的分析方法。在这项研究中，我们通过气相色谱（GC）分析和样品表征了四种常用拟除虫菊酯的顺式联苯菊酯（cis-BF），氯菊酯（PM），氯氰菊酯（CP）和氯氟氰菊酯（CF）的稳定性。制备。发现在加热或水中，顺式-BF和PM的立体异构体稳定，而CP和CIF的立体异构体不稳定。异构体转化仅发生在CIP或CF中的aC处，导致分析物立体异构体转化为差向异构体。 GC入口温度为260＆DEG; C，CIP和CF大约发生了9％的转化。在有机溶剂和无菌水中，顺式-BF和PM的立体异构体是稳定的，但在室温下水中的CP和CF的异构体转化较慢。但是，当GC入口温度保持在＆LE;时，CP和CF的异构体转化率相对较小（2-3％）。 180＆DEG; C或使用柱上进样时。水中αC的异构体转化表明，非生物过程也可能有助于在环境中观察到具有不对称αC的拟除虫菊酯的对映选择性。

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