UPLC-MS/MS非衍生化法测定茶叶中草甘膦及其代谢产物

Determination of Glyphosate and Its Metabolite Aminomethyl Phosphonic Acid in Tea by Non-derivatization Ultra Performance Liquid Chromatography Tandem Mass Spectrometry

试验利用超高效液相色谱串联质谱,建立直接测定茶叶中草甘膦及其代谢产物氨甲基膦酸的分析方法。样品用超纯水、二氯甲烷振荡提取,上清液经ProElut GLY柱净化,流出液过滤后直接检测。结果表明,草甘膦及氨甲基膦酸在1~1 000μg/L质量浓度范围内线性关系良好,线性相关系数r2均大于0.99。两者的检出限为0.003 mg/kg。向空白茶叶基质中添加0.1, 0.2和0.5 mg/kg草甘膦及氨甲基膦酸混合标准溶液,按上述方法处理分析后,草甘膦的回收率为89.3%~98.5%,氨甲基膦酸的回收率为91.3%~102.4%,相对标准偏差(S_(RSD))均在5.6%~8.3%之间(n=5)。应用该方法对市场购入的茶叶样品进行检测,草甘膦的检出率达30.5%。该方法前处理简便快速、准确性好、灵敏度高,能够满足大批量茶叶中草甘膦和氨甲基膦酸残留的检测需要。

A non-derivatization method was established for the direct determination of glyphosate and its metabolite aminomethyl phosphonic acid in tea using ultra-high performance liquid chromatography tandem mass spectrometry. After being extracted with ultrapure water and dichloromethane, samples were purified by ProElut GLY column and the effluent was directly detected after filtration. The results showed that the linear relationship between glyphosate and aminomethyl phosphonic acid was good in the mass concentration ranging from 1 to 1 000 μg/L, and the linear correlation coefficient r2 was greater than 0.99. The detection limit for glyphosate and aminomethylphosphonic acid was 0.003 mg/kg. The mixed standard of glyphosate and aminomethyl phosphonic acid with concentrations of 0.1, 0.2 and 0.5 mg/kg was added to the blank tea matrix. After processing and analysis according to the above method, the recovery of glyphosate and aminomethylphosphonic acid was in the range of 89.3%-98.5% and 91.3%-102.4%, respectively. The relative standard deviation(S_(RSD)) of two compounds was between 5.6% and 8.3%. The established method was used to determine the quality of tea purchased from the market. The detection rate of glyphosate was 30.5%. The method had the advantages of simple and rapid pretreatment, good accuracy and high sensitivity, and could meet the detection needs of glyphosate and aminomethylphosphonic acid residues in large quantities of tea.