Laboratory Services Branch, Ontario Ministry of the Environment, 125 Resources Road, Etobicoke, Ontario M9P3V6, Canada.
J Chromatogr A. 2011 Aug 19;1218(33):5638-43. doi: 10.1016/j.chroma.2011.06.070. Epub 2011 Jun 26.
Analysis of the broad-spectrum herbicide glyphosate and its related compounds is quite challenging. Tedious and time-consuming derivatization is often required for these substances due to their high polarity, high water solubility, low volatility and molecular structure which lacks either a chromophore or fluorophore. A novel liquid chromatography/tandem mass spectrometry (LC/MS-MS) method has been developed for the determination of glyphosate, aminomethylphosphonic acid (AMPA) and glufosinate using a reversed-phase and weak anion-exchange mixed-mode Acclaim® WAX-1 column. Aqueous environmental samples are directly injected and analyzed in 12 min with no sample concentration or derivatization steps. Two multiple reaction monitoring (MRM) channels are monitored in the method for each target compound to achieve true positive identification, and ¹³C, ¹⁵N-glyphosate is used as an internal standard to carry out isotope dilution mass spectrometric (IDMS) measurement for glyphosate. The instrument detection limits (IDLs) for glyphosate, AMPA and glufosinate are 1, 2 and 0.9 μg/L, respectively. Linearity of the detector response with a minimum coefficient of determination (R² value (R² > 0.995) was demonstrated in the range of ∼10 to 10³ μg/L for each analytes. Spiked drinking water, surface water and groundwater samples were analyzed using this method and the average recoveries of analytes in three matrices ranged from 77.0 to 102%, 62.1 to 101%, 66.1 to 93.7% while relative standard deviation ranged from 6.3 to 10.2%, 2.7 to 14.8%, 2.9 to 10.7%, respectively. Factors that may affect method performance, such as metal ions, sample preservation, and storage time, are also discussed.
分析广谱除草剂草甘膦及其相关化合物极具挑战性。由于这些物质的极性高、水溶性高、挥发性低且分子结构缺乏发色团或荧光团，因此通常需要繁琐且耗时的衍生化。本文建立了一种基于反相和弱阴离子交换混合模式 Acclaim® WAX-1 柱的高效液相色谱/串联质谱（LC/MS-MS）方法，用于测定水样中的草甘膦、氨甲基磷酸（AMPA）和草铵膦。环境水样无需浓缩或衍生化，直接进样，在 12 min 内完成分析。该方法中，每个目标化合物均采用两种多重反应监测（MRM）通道进行监测，以实现真正的阳性鉴定，并采用 ¹³C, ¹⁵N-草甘膦作为内标，进行草甘膦的同位素稀释质谱（IDMS）测量。草甘膦、AMPA 和草铵膦的仪器检测限（IDLs）分别为 1、2 和 0.9 μg/L。在 10 至 10³ μg/L 范围内，每个分析物的检测器响应均具有良好的线性关系，最小决定系数（R² 值）（R²＞0.995）。采用该方法分析了加标饮用水、地表水和地下水样品，三种基质中分析物的平均回收率为 62.1%至 102%、66.1%至 93.7%，相对标准偏差为 2.7%至 14.8%、2.9%至 10.7%。此外，还讨论了可能影响方法性能的因素，如金属离子、样品保存和存储时间等。
