HPLC-MS-MS法测定茶叶中的草甘膦和氨甲基膦酸

建立了茶叶中草甘膦（ PMG）及其主要代谢物氨甲基膦酸（ AMPA）残留检测的高效液相色谱-串联质谱法。样品经水超声,混合相固相萃取小柱净化,加9-芴基甲基三氯甲烷（ FMOC-Cl）溶液在硼酸盐缓冲溶液进行衍生化,采用电喷雾离子源、正离子扫描模式和多反应监测模式质谱检测,内标法定量。方法的定量检测低限为0.05 mg/kg,在1.0~20μg/L范围内线性良好,相关系数r2大于0.99,茶叶基质中, PMG和AMPA的3个加标水平下的回收率为65.5%~84.0%,相对标准偏差（ RSD, n=6）为3.5%~10.4%。该方法简单、准确性好,能满足日常检测工作的要求。

Determination of Glyphosate and Aminomethylphosphonic Acid Residues in Tea by HPLC-MS/MS

A method was developed for the determination of glyphosate （ PMG ） and aminomethylphosphonic acid （ AMPA） in tea using high performance liquid chromatography-tandem mass spectrometry （ HPLC-MS/MS） . The PMG and AMPA were extracted with water under ultrasonication, and cleaned-up using a mixed-mode solid phase extraction （ SPE） cartridge, then PMG and AMPA were derivatized using 9-fluorenylmethoxycarbonyl （ FMOC-Cl） in borate buffer. The detection of target compounds was performed by MS under electrospray ionization source, positive scanning mode and multiple reaction monitoring （ MRM） . The internal standard method was used for the quantitative analysis. The limit of quantification （ LOQ） was 0. 05 mg/kg. Calibration curves of pesticide were linear between 1. 0 μg/L and 20 μg/L, with correlation coefficients of more than 0. 99. The recoveries of PMG and AMPA in tea ranged from 65. 5% to 84. 0%, with relative standard deviations （ RSDs） were between 3. 5% and 10. 4%. The method was simple, accurate and can meet the requirements for daily food determination.