LC-MS/MS法测定茶叶中草甘膦残留量

Determination of Glyphosate Residues in Tea by LC-MS/MS

本文建立了液相色谱-质谱/质谱(LC-MS/MS)法测定茶叶中草甘膦残留量的方法。试样用纯水超声提取,分别经二氯甲烷、草甘膦专用固相萃取柱净化,再与氯甲酸(9-芴甲基)酯衍生,通过基质曲线校正、同位素内标法定量。实验结果表明,草甘膦在2.0~100.0μg/L线性关系良好,相关系数大于0.997。该方法检出限为0.01mg/kg,在0.04、0.2、1.0mg/kg三个浓度水平的加标回收率为87.5%~97.4%,相对标准偏差(RSD,n=6)为3.3%~6.1%。

A liquid chromatography-tandem mass spectrometry(LC-MS/MS) method was developed for the determination of glyphosate residues in tea. The samples were ultrasonic extracted with pure water, purified by dichloromethane and glyphosate special solid phase extraction column, and then derived with 9-fl uorenylmethylchloroformate(FMOC-Cl). In order to improve the accuracy of the results, matrix curve correction and isotope internal standard method were used to quantify the results. The results showed that the linear range of glyphosate was from 2.0μg/L to 100.0 μg/L. The correlation coeffi cient was greater than 0.997, and the limits of detection were 0.01mg/kg. The recoveries were 87.5% ~ 97.4 % at 0.04, 0.2and 1.0mg/kg, and the relative standard deviations(RSD, n=6) were 3.3% ~ 6.1%.