优化衍生条件应用GC-MS/MS测定蔬菜中二硫代氨基甲酸酯(盐)类农药残留

Determination of dithiocarbamate(salt)pesticide residues in vegetables by GC-MS/MS and optimizing the derivatization conditions

目的通过优化衍生条件,建立基于气相色谱串联三重四极杆质谱联用仪(GC-MS/MS)测定蔬菜中二硫代氨基甲酸酯(盐)类农药残留的方法。方法样品匀浆,经40%氯化亚锡-盐酸溶液(SnCl2-HCl)衍生后,用正己烷萃取,再用GC-MS/MS测定正己烷中的CS2的量,并测定标准系列溶液,绘制标曲;同时用福美双标准液测试转化率。结果方法浓度为0.02~10 mg/L,线性相关系数为0.999 9,精密度为1.82%~3.86%,回收率为98.2%~108.4%,检出限为0.001 mg/kg,且福美双的转化率为90.4%~107.6%。对广州市212份蔬菜样品进行检测,超标率仅为0.5%。结论该方法有优秀的宽线性、较好的精密度和准确度。广州市蔬菜样品中二硫代氨基甲酸酯(盐)类农药带来的食品安全风险极低。

Objective To establish a method for the determination of dithiocarbamate(salt) pesticide residues in vegetables by using gas chromatography-triple quadrupole mass spectrometry(GC-MS/MS) and optimizing the derivatization conditions.Methods After homogenized, the samples were derived by 40% stannous chloride-hydrochloric acid solution(SnCl2-HCl),and then were extracted by adding n-hexane.GC-MS/MS was used to determine the amount of CS2 in n-hexane, and the standard series solutions were determined, followed by the preparation of the standard curve.The conversion rate was tested by using the thiram standard.Results The concentration of dithiocarbamate(salt) detected by the method was 0.02–10 mg/L,the linear correlation coefficient was 0.999 9,the precision was 1.82%–3.86%,the recovery rate was 98.2%–108.4%,the detection limit was 0.001 mg/kg, and the conversion ratio of thiram was 90.4%–107.6%.A total of 212 vegetable samples were detected in Guangzhou, and the exceeding standard rate was only 0.5%.Conclusion The work established a method with excellent linearity in a wide range, as well as superior precision and accuracy.The food safety risk caused by dithiocarbamate(salt) pesticides in vegetables was extremely low in Guangzhou.