分散固相萃取/衍生化-高效液相色谱-串联质谱法同时测定水和食品中草甘膦、草铵膦和氨甲基膦酸残留

Simultaneous determination of glyphosate, glufosinate and aminomethyl residues in water and foods by dispersive solid phase extraction/derivatization-high performance liquid chromatography-tandem mass spectrometry

目的建立高效液相色谱-串联质谱法测定水和食品中草甘膦、草铵膦和氨甲基膦酸的残留量。方法样品经纯水涡旋超声提取,二氯甲烷去除脂肪,C_(18)分散固相萃取净化,(水样)净化液在硼酸盐缓冲液中加入9-芴基甲基三氯甲烷(FMOC-Cl)丙酮溶液进行衍生化2 h以上,经0.22μm微孔滤膜过滤,经CAPCELLCORE C_(18)柱分离,用5 mmol/L乙酸铵溶液和乙腈为流动相梯度洗脱,采用电喷雾负离子多反应监测模式检测,外标法定量。结果草甘膦、草铵膦和氨甲基膦酸在0.5~40μg/L浓度范围内呈良好的线性关系(r>0.999),方法定量限为0.5μg/kg。在0.5、5.0和20μg/kg添加水平时,平均回收率为70.1%~104.1%,相对标准偏差为0.6%~8.9%(n=6)。结论该方法分析速度快,净化效果好,杂质干扰小,回收率高,重复性好,适用于水和食品中草甘膦、草铵膦和氨甲基氨酸留量的测定。

Objective To establish a method for determination of glyphosate,glufosinate and aminomethyl residues in water and foods by high performance liquid chromatography-tandem mass spectrometry （HPLC-MS/MS）.Methods The samples were extracted by pure water vortex with ultrasound,and defatted with dichloromethane,then purified by C18 dispersive solid phase extraction column.Purified liquid （water） was adjusted pH by phosphate saline buffer and added 9-fluorene methyl chloroform （FMOC-C1） acetone solution for derivatization for 2 h at least.Derived compounds were filtered through 0.22 μm millipore membrane.The sample extract was separated by CAPCELLCORE C18 column with 5 mmol/L ammonium acetate-acetronitrile as mobile phase for gradient elution,and then identified by electrospray ionization （ESI） in negative mode and multiple reaction monitoring mode,and quantified with external standard method.Results The method showed good linear relationships in the range of 0.5-40 μg/L for glyphosate,glufosinate and aminomethyl with the correlation coefficients 〉 0.999.The limits of quantitation （LOQ） were 0.5 μg/kg.The average recovery rates spiked at levels of 0.5,5.0 and 20 μg/kg were 70.1%-104.1% with the relative standard deviations of 0.6%-8.9% （n=6）.Conclusion This method has rapid analysis speed,good purification effect,low impurity interference,high recovery rate and good repeatability,which is suitable for the determination of glyphosate,glufosinate and aminomethyl residues in water and foods.