New approach for determination of glyphosate and AMPA at sub-ppb levels by UHPLC-MS/MS.

REPETTI, MARÍA ROSA; DEMONTE, LUISINA; MICHLIG, NICOLÁS; GARCÍA, SILVIA; DE JESÚS, JUAN JOSÉ; BELDOMÉNICO, HORACIO

San Francisco

Congreso; 13th IUPAC International Congress of Pesticide Chemistry; 2014

A simplified method for the determination of glyphosate and AMPA in food and environmental samples based in FMOC derivatization and UHPLC MSMS is presented. Briefly the method involves an overnight reaction step followed by L-L partition with dichloromethane, yielding a 6-fold concentration of the sample. Sample preparation assays comprised optimization of sample size, extraction solvent ratio (sediments), FMOC derivatization steps (reagents, reaction time, pH) and the clean-up process (solvents for liquid-liquid partition). Validation of methodology following SANCO/12495/2011 specifications was achieved. The method presented satisfactory performance with recoveries between 85-110 % at two concentration levels (LOQ and 100 ppb) and LODs below of 0.5 ppb. The developed methodology was applied to different kind of samples: vegetal origin food, water and sediments from Santa Fe (Argentina). The simplified method showed advantages compared existent approaches, being a contribution the challenge of measuring the glyphosate family with simpler, economic and reliable methods.