原理 尿中的杀虫脒(包括游离的对氯邻甲苯胺)在碱性条件下,可用石油醚等有机溶剂萃取,然后用酸性溶液由有机相中反萃取。萃取出的杀虫脒在碱性条件下水解,生成对氯邻甲苯胺,后者经重氮化、偶联反应,生成红色偶氮染料后比色定量。 尿中游离的对氯邻甲苯胺,可不经水解而直接显色测定;所以,经水解、显色所测得的吸 Principle Chlordimeform (including free para-o-toluidine) in urine can be extracted with organic solvents such as petroleum ether under alkaline conditions and then back-extracted from the organic phase with an acidic solution. The extracted chlordimeform is hydrolyzed under alkaline conditions to form p-chloro-o-toluidine, which is diazotized and coupled to form a red azo dye and then colorimetrically quantified. Free o-chloro-o-toluidine, without hydrolysis and direct color determination; therefore, hydrolysis, color measured by the absorption