Simultaneous and sensitive analysis of glyphosate, glufosinate, and their metabolites in surface water by HPLC-ICP-MS/MS

Organophosphorus pesticides such as glyphosate and glufosinate are used worldwide, and environmental regulatory values are being adopted in many countries due to their potential toxicity. In the present work, a pretreatment-free analytical method is established in which these two compounds with their metabolites are isolated from each other by anion-exchange HPLC using ammonium acetate (70 mM, pH 3.7) as eluent, and they are detected by triple quadrupole ICP-MS. Very low detection limits of 0.03-0.17 μg L^-1 are acquired through the detection of P⁺ as PO⁺ via oxygen reaction mode, and quantitative recovery was obtained from the spike-recovery test on river water samples containing phosphate ion as an isobaric interferent. In addition, a constant sensitivity per molar concentration was achieved regardless of the compounds due to the powerful ion source of ICP-MS. This property suggests that semi-quantitative analysis of unknown P-bearing compounds is possible from one calibration curve.