咪鲜胺及其代谢产物在橙汁中的残留检测方法研究

Determination of Residuce of Prochloraz and Its Metabolite in Orange Juice

采用气相色谱电子捕获检测器（GC-ECD）研究了咪鲜胺及其代谢产物在橙汁中的残留检测方法,使用石油醚：丙酮（8∶2,V/V）提取,石油醚萃取净化,将咪鲜胺及其代谢产物在高温下与吡啶盐酸盐反应,待全部转化成其代谢产物2,4,6-三氯苯酚后进行测定。其在橙汁中的最小检出量为10-11 g,最低检测浓度为0.01mg/kg,咪鲜胺在橙汁中的平均添加回收率为72.5-109.1%,变异系数在5.7-9.7%之间,符合农药残留分析的要求。研究结果表明,咪鲜胺在常温和冷冻条件下的消解半衰期分别为：56.3d和105.0d。表明咪鲜胺在冷冻条件下降解缓慢。本实验优化了咪鲜胺衍生化过程与净化方法,具有快速准确、毒性小、灵敏度高、可同时检测多个样品等特点。

A GC method for the determination of residue of prochloraz and its metabolite in orange juice was described in this paper.The samples were extracted with petroleum ether-acetone（8∶2,by vol）,the extractant then re-extracted with petroleum ether by liquid-liquid extraction.prochloraz and metabolite reacted with pyridine chloride at high temperature,the product 2,4,6-trichlorophenol was detected.The limit of detection of the method was 10-11 g,the limit of concentration detected was 0.01 mg/kg.The recoveries of prochloraz in orange juice were between 72.5% and 109.1%,with a coefficient of variation between 5.7% and 9.7%,which met with the requirements of pesticide residue analysis.The results showed that the half-lives of prochloraz in room temperature and freezing environment condition were 56.4 d and 105.0 d respectively,it showed that the degradation of prochloraz was slow in freeze.The method described here with optimization of the derivation and purification of prochloraz is more accurate and sensitive than that of the previous procedures.