离子色谱法测定食品中草铵膦、草甘膦和氨甲基膦酸的残留

Determination of glyphosate glufosinate and(aminomethyl) phosphonic acid residues by ion chromatography

目的建立一种简单、快捷、同时测定食品中草铵膦、草甘膦、氨甲基膦酸残留量的离子色谱分析方法。方法样品用水提取后使用乙腈沉淀氨基酸和蛋白质,离心后取上清液依次过Dionex OnGuardⅡRP柱和Dionex OnGuardⅡAg/H柱,流出液经IonPac AS11-HC离子色谱柱(含AG11-HC保护住)分离,用KOH淋洗液自动发生器(EG)进行梯度淋洗,抑制器采用外加水模式,电导检测器检测。结果结果表明草甘膦和草铵膦在0.02~6.25 mg/L、氨甲基膦酸在2.00~62.5 mg/L范围内线性关系良好,相关系数均大于0.999,Gly、Gluf和AMPA的方法检出限分为0.047、0.033和0.520 mg/kg,定量限分为0.16、0.11和1.73 mg/kg,回收率为80.1%~109%,日内精密度(n=6)为0.91%~12.5%,日间精密度(m=5)小于10.0%。结论该方法具有净化效果好、定量准确、灵敏快速的特点,适用于食品中草铵膦、草甘膦、氨甲基膦酸残留量的检测确证,能达到GB 2763-2014的检测要求。

Objective To establish a rapid,simple and simultaneous analytical method for the determination of glyphosate（Gly）,glufosinate（Gluf） and（aminomethyl）phosphonic acid（AMPA） residues in food by ion chromatography.Method The amino acid and protein in food were precipitated with acetonitrile.The impurities and Cl^- in the supernatant were removed by a Dionex OnGuard Ⅱ RP column and a Dionex OnGuard Ⅱ Ag/H column,respectively.The filtrate was separated on an IonPac AS-11 column with KOH solution as eluent.A suppressor with external water mode and a conductivity detector were used for the detection.Results Under the experimental conditions,the calibration curves of Gly and Gluf were linear in the range of 0.02~6.25 mg/L,and AMPA was linear in the range of 2.00~62.5 mg/L with correlation coefficients all over 0.999.The limits of detection（LODs） for Gly,Gluf and AMPA were 0.047,0.033 and 0.520 mg/kg,and the limits of quantitation of the method（LOQs） were 0.16,0.11 and 1.73 mg/kg,respectively.The mean recoveries of 3 compounds in spiked food ranged from 80.1%to 109%with the intra-day precisions（n=6） in the range of 0.91%~12.5%and inter-day precisions（n=5）less than 10.0%.Conclusion This method can meet the requirements of GB 2763-2014 and suitable for the identification and quantitation of Gly,Gluf and AMPA in food due to its simplicity and accuracy.