Development of a UHPLC-MS/MS method to enhance the detection of Glyphosate, AMPA and Glufosinate at sub-microgram / L levels in water samples

Glyphosate is the best-selling herbicide worldwide. The toxicity on ecosystems and the possible effects on human health have long been at the centre of a complex controversy concerning the authorisation for its use. The peculiar chemical-physical properties of glyphosate, AMPA and glufosinate make their determination at trace levels in the water a real analytical challenge. All three compounds can be derivatised to less polar ones and FMOC-Cl (9-fluorenylmethyl chloroformate) is the most common pre-column derivatisation reagent used for this analysis. It can be successfully combined with Ultra-High-Performance Liquid Chromatography with Mass Spectrometry (UHPLC-MS/MS) to determine all three analytes in one method as part of water monitoring programs. The developed method aims to determine glyphosate with AMPA and glufosinate at sub-micrograms/L levels in groundwater, surface and water by UHPLC-MS/MS after derivatisation with FMOC-Cl. The novelty of this method is its high simplicity, robustness and sensitivity allowing the identification and quantification of the compounds at the detection limits required by the European regulations (0.1 µg /L). No pre-concentration or purification steps (by using Solid Phase Extraction cartridges) are necessary for our method saving time and consumables costs. The method demonstrated an excellent linear relationship (R2 ≥ 0.999) in the concentration range from 0.025 to 10 µg /L for glyphosate and AMPA and 0.025 to 5 µg /L for glufosinate. The method Limit Of Quantification (LOQ) is 0.025 µg/L, the lowest among all previously published studies, and it was demonstrated according to the European SANTE guidelines.