Quantitative determination of glyphosate in human serum by 1H NMR spectroscopy

The determination and quantification of glyphosate in serum using 1H NMR spectroscopy is reported. This method permitted serum samples to be analysed without derivatization or any other sample pre-treatment, using 3-trimethylsilyl 2,2′,3,3′-tetradeuteropropionic acid (TSP-d4) as a qualitative and quantitative standard. Characterization of the herbicide N-(phosphonomethyl)glycine was performed by analysing chemical shifts and coupling constant patterns. Quantification was performed by relative integration of CH2-P protons to the TSP-d4 resonance peak. The method was tested for repeatability (n = 5) and yielded coefficients of variation of 1% and 3%, respectively: detection and quantification limits were also determined and were 0.03 and 0.1 mmol/L, respectively. The method was applied to the quantification of glyphosate in a case of acute poisoning.