This study represents the initial examination of the herbicidal efficacy, crop safety, and degradation patterns of 2,4-D ethylhexyl ester (2,4-D EHE) at the enantiomeric level. Baseline separation of 2,4-D EHE enantiomers was achieved using a superchiral R-AD column, with their absolute configurations determined through chemical reaction techniques. Evaluation of weed control efficacy against sensitive species such as sun spurge and flixweed demonstrated significantly higher inhibition rates for S-2,4-D EHE compared to R-2,4-D EHE. Conversely, no stereoselectivity was observed in the fresh-weight inhibition rates of both enantiomers on crops or nonsensitive weeds. A sensitive HPLC-MS/MS method was developed to simultaneously detect two enantiomers and the metabolite 2,4-D in plants. Investigation into degradation kinetics revealed no substantial difference in the half-lives of R- and S-2,4-D EHE in maize and flixweed. Notably, the metabolite 2,4-D exhibited prolonged persistence at elevated levels on flixweed, while it degraded rapidly on maize.

中文翻译：

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手性除草剂 2,4-D 乙基己酯：绝对构型、立体选择性除草活性、作物安全以及对玉米和浮草的代谢行为


本研究首次对 2,4-D 乙基己酯 (2,4-D EHE) 在对映体水平上的除草功效、作物安全性和降解模式进行了研究。使用超手性 R-AD 柱实现 2,4-D EHE 对映体的基线分离，并通过化学反应技术确定其绝对构型。对敏感物种（例如太阳大戟和浮草）的杂草控制效果评估表明，与R -2,4-D EHE 相比， S -2,4-D EHE 的抑制率显着更高。相反，两种对映体对作物或不敏感杂草的鲜重抑制率没有观察到立体选择性。开发了一种灵敏的 HPLC-MS/MS 方法来同时检测植物中的两种对映体和代谢物 2,4-D。降解动力学研究表明， R - 和S -2,4-D EHE 在玉米和浮草中的半衰期没有显着差异。值得注意的是，代谢物 2,4-D 在浮草上表现出长时间的高水平持久性，而在玉米上则迅速降解。