Glyphosate is currently the most widely used herbicide in the world; however, the zwitterionic and highly polar properties of glyphosate make current pesticide analysis methods unsuitable for its trace analysis in natural waters. Additionally, current glyphosate analysis methods do not account for waters of varying hardness, which is vital as glyphosate can complex with cationic species such as Ca²⁺ and Mg²⁺ in the environment. We detail here a robust LC-MS/MS method for the quantitation of glyphosate and its primary transformation product aminomethylphosphonic acid (AMPA) in environmental waters of varying water hardness. Chromatographic separation was achieved with a reversed-phase and weak anion-exchange mixed-mode column. We found that the addition of EDTA into hard water samples increases the response of both glyphosate and AMPA in the mass spectrometer. Limits of detection of 0.23 and 0.30 μg L⁻¹ for glyphosate and AMPA in EDTA-amended hard water were achieved, respectively. We have demonstrated that the accuracy of the method was consistent over a wide range of water hardness levels up to a maximum of ~340 mg mL⁻¹ CaCO₃ hardness. We validated the method using matrix fortification of uncontaminated environmental samples from US river water. We then demonstrated that the method was successful at quantifying glyphosate and AMPA across surface and drinking water samples of varying water hardness from North Carolina and Sri Lanka. Measured concentrations of glyphosate and AMPA ranged from 1.6 to 13 μg L⁻¹ and 0.50 to 2.5 μg L⁻¹, respectively. This study represents a significant increase in sensitivity for LC-MS/MS analysis of glyphosate in hard water systems.

草甘膦是目前世界上使用最广泛的除草剂；然而，草甘膦的两性离子和高极性特性使得当前的农药分析方法不适用于天然水中的痕量分析。此外，当前的草甘膦分析方法无法考虑不同硬度的水，这一点至关重要，因为草甘膦可以与环境中的阳离子物质（例如 Ca ²⁺和 Mg ^2+）络合。我们在此详细介绍了一种稳健的 LC-MS/MS 方法，用于定量不同水硬度的环境水中的草甘膦及其初级转化产物氨甲基膦酸 (AMPA)。使用反相弱阴离子交换混合模式柱实现色谱分离。我们发现，在硬水样品中添加 EDTA 会增加质谱仪中草甘膦和 AMPA 的响应。 EDTA 修正硬水中草甘膦和 AMPA 的检测限分别为 0.23 和 0.30 μg L ^-1 。我们已经证明，该方法的准确性在各种水硬度水平（最高可达~340 mg mL ^-1 CaCO ₃硬度）上都是一致的。我们使用美国河水中未受污染的环境样品的基质强化来验证该方法。然后，我们证明该方法成功地定量了北卡罗来纳州和斯里兰卡不同硬度的地表水和饮用水样品中的草甘膦和 AMPA。测得的草甘膦和AMPA浓度范围分别为1.6至13μg L ^-1和0.50至2.5 μg L ^-1 。 这项研究表明硬水系统中草甘膦的 LC-MS/MS 分析灵敏度显着提高。