Determination of glyphosate and aminomethylphosphonic acid residues in water by gas chromatography with tandem mass spectrometry after exchange ion resin purification and derivatization. Application on vegetable matrixes

An analytical method for the determination of glyphosate and its principal metabolite, aminomethylphosphonic acid (AMPA), in water of different hardne sses (5, 20, and 30 degrees DH, french hardness) has been developed. Sample s were fortified at different levels (0.05, 0.1, 1, and 5 mu g/L) and were purified by column chromatography on ion-exchange resins, After derivatizat ion with TFAA/HFB mixture, the derivatives were quantified by using capilla ry gas chromatography with an ion-trap tandem mass spectrometric detector. Analytical conditions for MS/MS detection were optimized, and the quantific ation was carried out on the sum of areas of the three most representative ions: m/z 283, 223, and 181 for AMPA and m/z 440, 321, and 261 for glyphosa te. The Limit of quantification was demonstrated to be at 0.05 mu g/L for e ach compound. The mean recovery value and the relative standard deviation ( n = 65) were 93 and 12% for AMPA and 95 and 13% for glyphosate.