基于改进的QuEChERS结合UPLC-MS/MS技术测定大米中4种杀虫剂类农药的不确定度评定

Evaluation of Uncertainty in the Determination of Four Pesticides in Rice Based on Improved QuEChERS Combined with UPLC-MS/MS Technology

对采用改进的QuEChERS结合超高效液相色谱串联质谱(UPLC-MS/MS)法测定大米中4种杀虫剂类农药测量值的不确定度进行评定。根据JJF 1135-2005《化学分析测量不确定度评定》和JJF 1059.1-2012《测量不确定度评定与表示》中的有关规定和基本程序,建立大米中4种杀虫剂类农药含量不确定度的数学模型,对测定过程中的不确定度来源进行分析和合成。结果显示:当4种杀虫剂类农药含量分别为9.18μg/kg、8.81μg/kg、8.26μg/kg和7.95μg/kg时,其扩展不确定度依次为1.49μg/kg、1.65μg/kg、1.40μg/kg和1.51μg/kg(k=2,P=95%)。影响测定结果的主要因素是被测物质量浓度,其次是样品测量的重复性、样品称量、净化液稀释、加标回收率、分析仪器和提取溶液加入体积。该方法适用于改进的QuEChERS结合UPLC-MS/MS法测定大米中杀虫剂类农药的不确定度评定,以对大米中杀虫剂类农药的检测结果的可靠性提供科学依据。

the uncertainty of four pesticides in rice was evaluated by improved QuEChERS combined with UPLCMS/MS.According to the relevant provisions and basic procedures of JJF 1135-2005“Evaluation of Measurement Uncertainty in Chemical Analysis”and JJF 1059.1-2012“Evaluation and Expression of Measurement Uncertainty”,a mathematical model for the uncertainty of the content of four pesticides in rice is established and the sources of uncertainty in the determination process are analyzed and synthesized.The results showed that when the contents of four pesticides were 9.18,8.81,8.26,7.95μg/kg,respectively,the expanded uncertainty was 1.49,1.65,1.40,1.51μg/kg(k=2,P=95%),respectively.The main factors affecting the determination results were the mass concentration of the measured substance,followed by the repeatability of sample measurement,sample weighing,purification solution dilution,the recovery rate of standard addition,analytical instrument and the volume of extraction solution.This method is applicable to the uncertainty evaluation of the improved QuEChERS combined with UPLCMS/MS method for the determination of pesticides in rice,so as to provide a scientific basis for the reliability of the detection results of pesticides in rice.