改进的QuEChERS法结合UPLC-MS/MS测定小米中23种农药残留

Determination of 23 Pesticide Residues in Millet by Improved QuEChERS Method Combined with UPLC-MS/MS

目的:建立改进的QuEChERS技术结合UPLC-MS/MS法测定小米中23种农药残留的分析方法。方法:小米样品水化后经乙腈提取,QuEChERS法净化,C_(18)色谱柱分离,以5 mmol/L甲酸铵水溶液和5 mmol/L甲酸铵甲醇溶液作为流动相进行梯度洗脱,电喷雾正离子模式(ESI+)电离,多反应监测模式(MRM)检测,基质标准溶液匹配外标法定量。结果:23种农药在1~100 μg/L线性关系良好,相关系数均大于0.999,方法的检出限(S/N=3)为0.27~1.15 μg/kg,定量限(S/N=10)为0.89~3.83 μg/kg。在定量限、2倍定量限和10倍定量限3个添加水平下,23种农药的回收率为63.29%~106.7%,相对标准偏差(n=6)为1.61%~9.27%。140份小米样品中,1份样品检出氯虫苯甲酰胺残留,5份样品检出丙环唑残留,6份样品的检出值均在限量要求以内,表明吉林省小米产品安全可靠。结论:该方法操作简单、灵敏度高、快速准确,适用于小米中农药多残留的检测。

Objective:A method for the determination of 23 pesticide residues in millet by UPLC-MS/MS was developed.Methods:The samples were extracted by acetonitrile after hydration,purified by QuEChERS method and separated by C_(18) column.Gradient elution was carried out with 5 mmol/L ammonium formate water and 5 mmol/L ammonium formate methanol as mobile phase.The compounds were ionized under electrospray positive ion mode (ESI+),detected under multiple reaction monitoring mode (MRM),and quantified by matrix matching standard solution external standard method.Results:The results showed that the linear range of the 23 pesticides ranged from 1 to 100 μg/L,and the correlation coefficients were more than 0.999.The detection limits (S/N=3) of the method were between 0.27 and 1.15 μg/kg,and the limits of quantification (S/N=10) were between 0.89 and 3.83 μg/kg.At the three spiked levels (1×limits of detection (LOQ),2×LOQ and 10×LOQ),the recoveries of 23 pesticides ranged from 63.29% to 106.7%,and the relative standard deviations (n=6) ranged from 1.61% to 9.27%.Among the 140 millet samples,chlorantraniliprole residue was detected in 1 sample,propiconazole residue was detected in 5 samples,and the detection values of 6 samples were all below the limit requirements,indicating that the millet products in Jilin province are safe and reliable.Conclusions:The method is simple,accurate and suitable for the determination of pesticide residues in millet.