Method for the determination of residues of the herbicide glyphosate and its principal metabolite,aminomethylphosphonic acid,in plant materials by nitrogen-selective gas chromatography

A method has been developed for the determination of residues of glyphosate and its major metabolite, aminomethylphosphonic acid, in stem tissues of blueberries and raspberries. This method involves extraction with water, removal of pigments by charcoal treatment followed by column chromatography using a cation-exchange resin for removal of sugar, a single-step derivatization reaction, and quantification by gas chromatography with a nitrogen-phosphorus detector. Limits of detection for glyphosate and its metabolite were 0.03 and 0.01 mg kg^?1, respectively, for both blueberry and raspberry stems.