Rapid and simple methods for the determination of Jiahuangxianjunzuo (JHXJZ) in paddy water, brown rice, soil and rice straw was developed and validated. This method involved the use of ultrahigh-performance liquid chromatography equipped with photodiode array detector. The most important factor was chromatographic conditions, as identified through an orthogonal experimental design. This method showed good recoveries and precisions, thereby indicating its suitability for monitoring of JHXJZ residues in paddy water, brown rice, soil and rice straw. Furthermore, hydrolysis experiment was conducted in the laboratory under pH = 7 buffer solutions, and its degradation product was identified as 2-(4-fluorophenyl)-5-methoxy-1,3,4-oxadiazole by high-resolution mass spectrometry. JHXJZ has a major degradation pathway in the water which the OH⁻ nucleophilic attack the C5 of 1,3,4-oxadiazole ring. Then it leaves mesyl to form intermediate 5-(4-fluorophenyl)-1,3,4-oxadiazol-2-ol and the intermediate combined with methanol formed the degradation product 2-(4-fluorophenyl)-5-methoxy-1,3,4-oxadiazole by the loss of one H₂O.The degradation pathways of JHXJZ under the present indoor simulation conditions were proposed.

中文翻译：

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新型杀菌剂2-（4-氟苯基）-5-（甲基磺酰基）-1,3,4-恶二唑的定性和定量分析及其在稻田水中的降解途径鉴定。

开发并验证了测定稻田水，糙米，土壤和稻草中的佳黄仙君佐（JHXJZ）的快速，简便方法。该方法涉及使用配备光电二极管阵列检测器的超高效液相色谱仪。最重要的因素是通过正交实验设计确定的色谱条件。该方法具有良好的回收率和精密度，从而表明它适用于监测稻田水，糙米，土壤和稻草中的JHXJZ残留量。此外，在实验室中在pH = 7的缓冲溶液中进行了水解实验，并通过高分辨率质谱将其降解产物鉴定为2-（4-氟苯基）-5-甲氧基-1,3,4-恶二唑。JHXJZ在水中的主要降解途径是⁻亲核攻击1,3,4-恶二唑环的C5。然后离开甲磺酰基形成中间体5-（4-氟苯基）-1,3,4-恶二唑-2-醇，该中间体与甲醇结合形成降解产物2-（4-氟苯基）-5-甲氧基-1，通过损失1个H ₂ O使3,4-恶二唑降解。提出了在室内模拟条件下JHXJZ的降解途径。