超高效液相色谱-串联质谱法测定茶叶中草甘膦和草铵膦的残留量

建立茶叶中草甘膦和草铵膦的残留超高效液相色谱法-串联质谱法快速检测方法。样品采用NaOH溶液提取后,HCl溶液调节酸度,经N-丙基乙二胺净化,氯甲酸(9-芴甲基)酯衍生化,正离子多反应监测测定,外标法定量。草甘膦和草铵膦在0.005～0.50μg/mL质量浓度范围内线性关系良好,相关系数(r)均大于0.995,草甘膦和草铵膦的检出限均为0.05 mg/kg,定量限均为0.08 mg/kg,在添加量为0.08、0.10、1.0、2.0、4.0 mg/kg时,草甘膦的回收率为75.6%～95.5%,相对标准偏差为3.24%～8.38%(n=10),草铵膦的回收率为76.0%～96.6%,相对标准偏差为3.05%～7.85%(n=10)。该方法样品前处理简单、分析时间短,回收率和精密度等均符合农药多残留检测技术的要求,适用于茶叶中草甘膦和草铵膦残留的同时检测。

Determination of Glyphosate and Glufosinate-Ammonium Residues in Tea by UPLC-MS/MS

A rapid method was developed for the determination of glyphosate (GLY) and glufosinate-ammonium (GLUF) in tea using ultra-high performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). The sample was extracted with NaOH solution and after pH adjustment with HCl, the extract was cleaned up with N-(n-propyl) ethyenediamine (PSA), and then was derivatized with 9-fluorenylmethyl chlorformate (FMOC-Cl) in borate buffer solution. The derivatives of GLY and GLUF were detected with positive electrospray ionization-mass spectrometry (ESI-MS/ MS) in the multiple reaction monitoring (MRM) mode. The quantification was performed by external standard method. The method showed a good linearity (r > 0.995) in the range of 0.005–0.50 μg/mL. The limit of detection (LOD) and the limit of quantization (LOQ) were 0.05 and 0.08 mg/kg for both GLY and GLUF, respectively. At spiked levels of 0.08, 0.10, 1.0, 2.0 and 4.0 mg/kg, the recoveries of GLY and GLUF were 75.6%–95.5% and 76.0%–96.6%, with relative standard deviations (RSDs) (n = 10) of 3.24%–8.38% and 3.05%–7.85%, respectively. This method proved to be simple and rapid, and its sensitivity and accuracy could meet the requirements for the simultaneous analysis of GLY and GLUF in tea.