超高效液相色谱串联质谱非衍生化法测定土壤中草甘膦及其代谢物氨甲基膦酸含量

为了建立土壤中草甘膦(Glyphosate）及其主要代谢物氨甲基膦酸(AMPA)残留的定量分析方法,采用固相萃取结合液相色谱串联质谱技术,样品以磷酸钠和柠檬酸三钠混合溶液提取,经固相萃取柱净化,采用正向亲水性液相色谱柱(Hilic)梯度洗脱,通过质谱的多反应监测(MRM)负离子模式扫描进行测定,外标法定量。结果表明:草甘膦、氨甲基膦酸的线性范围为0.02~0.2 μg/mL,相关系数(R²)分别为0.9995、0.9998,检出限分别为0.5 μg/kg和0.6 μg/kg,定量限分别为1.6 μg/kg和2.0 μg/kg;3个加标水平草甘膦的回收率在79.67%~96.17%之间,AMPA回收率在77.83%~99.47%之间,RSD值分别为3.95%~7.49%、1.96%~3.89%。与传统的柱前衍生方法相比,具有前处理简单、检出限低、灵敏度高的优点,完全可以适用于土壤中草甘膦的分析。

Glyphosate and Aminomethyl Phosphonic Acid in Soil: Determined by Direct Injection Liquid Chromatography-tandem Mass Spectrometry

In order to establish a quantitative analysis method for glyphosate and its major metabolite aminomethyl phosphonic acid (AMPA) residues in soil, the solid-phase extraction coupled with liquid chromatography-tandem mass spectrometry technology was used in this study. The sample was extracted with sodium sulfate and trisodium citrate, purified by solid phase extraction, isolated by hydrophilic liquid chromatographic column, detected by chromatography-tandem mass spectrometry under negative electro-spray ionization in the multiple reaction monitoring mode (MRM) and quantified by the external standard method. The results showed that the good linearity range of glyphosate and AMPA was 0.02-2 μg/mL, their correlation coefficients (R²) were 0.9995 and 0.9998. The limit of detection (LOD) of glyphosate and AMPA was 0.5 μg/kg and 0.6 μg/kg, respectively, and the limit of quantification (LOQ) was1.6 μg/kg and 2.0 μg/kg, respectively. The recovery of glyphosate and AMPA at three spiked concentration levels ranged from 79.67% to 96.17% and from 77.83% to 99.47%, respectively. RSD was 3.95%-7.49% and 1.96%-3.89%, respectively. Compared with the traditional derivatization method, this method has the advantages such as the simple operation, low LOD and high accuracy, and it is suitable for analyzing glyphosate and aminomethyl phosphonic acid in soil.