A modified clean‐up for the determination of glyphosate and its metabolite residues in lentils using high pressure liquid chromatography and post‐column fluorogenic labelling

Abstract

AbstractAn analytical method is presented for the analysis of glyphosate and its metabolite (aminomethyl)phosphonic acid (AMPA), in lentil samples. They were extracted from powdered samples with water and chloroform. The aqueous layer was acidified and passed through a cation exchange column. The eluate was made basic, passed through an anion exchange column in the hydroxide form and discarded. The latter column was eluted with hydrochloric acid (0.3 M) which was collected, evaporated under vacuum to 1 ml, diluted with water to 10 ml, filtered and analysed for glyphosate and metabolite using a liquid chromatograph with a post‐column reactor and a fluorescence detector. The limit of detection, average recovery and coefficient of variation (CV) were 0.08 μg g−1, 92.5% and 7.3% for glyphosate and 0.1 μg g−1, 92.5% and 8.3% for AMP A. The detector response was found to be linear within the range 20–400 ng.