液相色谱-串联质谱法测定茶叶中5种农药

Determination of 5 kinds of Pesticide Residues in Tea by Liquid Chromatography-Tandem Mass Spectrometry

建立多壁碳纳米管/QuEChERS结合高效液相色谱-串联质谱法测定茶叶中丁醚脲、甲基硫菌灵、氯噻啉、唑虫酰胺、氯虫苯甲酰胺5种农药残留的分析方法。茶叶样品经酸化乙腈提取,采用QuEChERS方法前处理,以N-丙基乙二胺(N-propyl ethylenediamine,PSA)、C_(18)、多壁碳纳米管(multi-walled carbon nanotubes,MWCNTs)净化,经乙腈-水(含0.1%甲酸)流动相体系洗脱,用C_(18)色谱柱分离,正离子电喷雾模式电离,多反应模式监测,外标法定量分析5种农药残留的含量。结果表明,茶叶中5种农药残留在0.1~50 ng/mL的质量浓度范围内线性良好,检出限为0.5~5.0μg/kg,定量限为1.0~12.5μg/kg,平均回收率为81.0%~97.6%,相对标准偏差为5.6%~9.9%。该方法快速、简便、准确,适用于茶中丁醚脲、甲基硫菌灵、氯噻啉、唑虫酰胺、氯虫苯甲酰胺5种农药残留的检测。

To establish a method for the determination of diafenthiuron,thiophanate-methyl,imidaclothiz,tolfenpyrad and chlorantraniliprole residues in tea by multiwalled carbon nanotubes/QuEChERS coupled with liquid chromatography-tandem mass spectrometry,the tea samples were extracted with acidic acetonitrile and purified by the optimized QuEChERS method,followed by clean up by PSA,C_(18),MWCNTs.A mobile phase system of acetonitrile-water(containing 0.1%formic acid)was used for elution,followed separated by C_(18) column.The content of 5 kinds of pesticide residues was external standard method for quantitative analysis by positive ion electrospray and multi-reaction monitoring mode.The results showed that the 5 pesticides showed good linearity in the concentration range of 0.5-50 ng/mL,the limits of detection were 0.5-5.0μg/kg,the limits of quantitation were 1.0-12.5μg/kg,the average recoveries were 81.0%-97.6%,and the relative standard deviations were 5.6%-9.9%.The method was rapid,simple and accurate and was suitable for the determination of diafenthiuron,thiophanate-methyl,imidaclothiz,tolfenpyrad and chlorantraniliprole residues in tea.