改进的固相萃取/高效液相色谱-串联质谱法测定茶叶中草甘膦和氨甲基膦酸残留量

Determination of glyphosate and aminomethyl phosphonic acid in tea by modified high performance liquid chromatography-tandem mass spectrometry with purification based on solid phase extraction

建立并优化了茶叶中的草甘膦(GLY)和氨甲基膦酸(AMPA)的固相萃取/高效液相色谱-串联质谱法的检测方法。样品用水-二氯甲烷体系提取后,经WondaSep Glyphosate固相萃取柱净化,在硼酸缓冲液中与氯甲酸-9-芴基甲酯(FMOC-Cl)进行衍生反应后,经InertSustainBio C18(100*2.1mm,3μm)色谱柱分离,以乙腈和5mmol/L乙酸铵溶液(含0.1%甲酸)为流动相进行梯度洗脱,MRM模式进行定性定量分析。结果表明:GLY和AMPA的线性范围为1～250μg/L,相关性好,r2≥0.9999;方法精密度以6次测定值的RSD表示,为0.8%～1.2%;方法回收率用3个浓度进行添加实验,回收率范围为79.4%～95.2%;定量限范围为6.5～8.0μg/kg;日内精密度的RSD(n=5)范围为2.7%～3.3%,日间精密度的RSD(n=9)范围为1.5%～2.2%。结论:本方法前处理简单,回收率高,重现性好,可作为茶叶中GLY和AMPA的有效检测方法。

The samples were extracted with water-dichloromethane,purified with WondaSep Glyphosate column,and derivatized with 9-fluorenylmethoxycarbonyl(FMOC-Cl)in borate buffer.The analysis was performed by HPLC-MS/MS system with InertSustainBio C 18(100*2.1 mm,3μm)column.Gradient elution was adopted with the mobile phase consisted of acetonitrile and 5 mmol/L ammonium acetate containing 0.1%formic acid.Furthermore,multiple-reaction monitoring(MRM)was performed to identify and quantify GLY and AMPA.Two linear calibration curves were obtained with r2≥0.9992.The precisions of the method were showed by RSD(n=6)ranging from 0.8%to 1.2%.The recoveries were investigated in three spiked levels and ranging from 79.4%to 95.2%.The range of LOQ was from 6.5μg/kg to 8.0μg/kg while the RSDs(n=9)of intra-day precision and inter-day precision were within 2.7%-3.3%and 1.5%-2.2%,respectively.The method is simple to detect GLY and AMPA in tea with good recovery and repeatability.