The rapid sulfhydrylation of chlorothalonil (CHT) in sulfur-rich vegetable matrices was observed in our previous study. However, the formation pathway, residual behavior, and toxicity of sulfhydrylated CHT remain unclear. In this study, we reveal that 4-sulfhydryl chlorothalonil (4-SH-CHT) can be formed by the reaction of CHT with H₂S species. CHT sulfhydrylation mainly occurs in tissue-destroyed pak choi, as H₂S and various H₂S donors are released along with tissue destruction. Over 50 % of CHT was transformed during pak choi homogenization at room temperature (25 °C). Liquid nitrogen with solvent acidification has been proposed to inhibit rapid sulfhydrylation during the analysis of CHT and its degradation products. The analytical method developed to simultaneously detect CHT, 4-SH-CHT, and 4-hydroxy chlorothalonil demonstrated good accuracy, high sensitivity, and satisfactory repeatability. At the maximum recommended dose of CHT, the terminal concentration of CHT in pak choi was higher than the maximum residue level, suggesting a potential chronic risk. The acute toxicity of 4-SH-CHT was higher than that of CHT, and the main target organs were the liver and heart. The consumption of 4-SH-CHT in several tissue-destroyed pak choi samples was higher than the threshold level. This study provides valuable information for further comprehensive safety evaluations of CHT in sulfur-rich vegetables and related foods.

中文翻译：

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白菜中百菌清的巯基化反应从培养到样品分析和暴露风险评估


在我们之前的研究中观察到百菌清 （CHT） 在富含硫的蔬菜基质中快速巯基化。然而，巯基化 CHT 的形成途径、残留行为和毒性仍不清楚。在这项研究中，我们揭示了 4-巯基百菌清 （4-SH-CHT） 可以通过 CHT 与 H₂S 物种反应形成。CHT 巯基化主要发生在组织破坏的 pak choi 中，因为 H₂S 和各种 H₂S 供体与组织破坏一起释放。在室温 （25 °C） 的白菜匀浆过程中转化了超过 50% 的 CHT。有人提出，溶剂酸化的液氮可在分析 CHT 及其降解产物过程中抑制快速巯基化。为同时检测 CHT、4-SH-CHT 和 4-羟基百菌清而开发的分析方法表现出良好的准确性、高灵敏度和令人满意的重现性。在 CHT 的最大推荐剂量下，白菜中 CHT 的终末浓度高于最大残留水平，表明存在潜在的慢性风险。4-SH-CHT 的急性毒性高于 CHT，主要靶器官为肝脏和心脏。几个组织破坏的白菜样品中 4-SH-CHT 的消耗量高于阈值水平。本研究为进一步全面评价富硫蔬菜和相关食品中 CHT 的安全性提供了有价值的信息。