Simultaneous Quantification of Glyphosate, Glufosinate, and Their Major Metabolites in Rice and Soybean Sprouts by Gas Chromatography with Pulsed Flame Photometric Detector

• Published in: Journal of agricultural and food chemistry 2004-06, Vol.52 (13), p.4057-4063
• Main Authors: Tseng, Su-Hsiang, Lo, Yi-Wen, Chang, Pi-Chiou, Chou, Shin-Shou, Chang, Hung-Min
• Format: Article
• Language: English
• Subjects: Aminobutyrates - analysis; Anions; bean sprouts; Biological and medical sciences; Cereal and baking product industries; Chromatography, Gas - methods; Chromatography, Ion Exchange; detectors; food analysis; food contamination; Food industries; Fundamental and applied biological sciences. Psychology; gas chromatography; General aspects; glufosinate; Glycine - analogs & derivatives; Glycine - analysis; Glycine max - chemistry; Glyphosate; herbicide residues; Herbicides - analysis; Isoxazoles; metabolites; Methods of analysis, processing and quality control, regulation, standards; Organophosphonates - analysis; Oryza - chemistry; Propionates - analysis; rice; soybeans; Tetrazoles
• ISSN: 0021-8561; 1520-5118
• DOI: 10.1021/jf049973z

Procedures were developed for the simultaneous determination of glyphosate [N-(phosphonomethyl)glycine] and glufosinate [dl-homoalanin-4-yl-(methyl)phosphinic acid] and their major metabolites, aminomethylphosphonic acid (AMPA) and 3-(methylphosphinico)propionic acid (3-MPPA), in rice and soybean sprouts by gas chromatography (GC) equipped with a pulsed flame photometric detector (PFPD). Herbicides and their major metabolites were previously derivatized with TMOA (trimethyl orthoacetate (TMOA) in the presence of acetic acid, and their GC responses versus heating temperature (70−90 °C) and heating time (30−120 min) were optimized. It was found that increases in heating temperature and heating time were unfavorable for the derivatization of glyphosate or glufosinate, whereas high temperature and extended reaction time remarkably facilitated that of AMPA and 3-MPPA except at 90 °C for an extended reaction time (120 min). Combination of AG1-X8 anion-exchange chromatography with a Florisil cartridge cleanup process was favorable for the GC-PFPD analysis. Four types of derivatives spiked in rice and soybean sprout matrices were eluted, reaching a baseline separation, in a sequence of 3-MPPA, AMPA, glyphosate, and glufosinate within 14 min using a DB-608 capillary column. Recoveries of glyphosate, AMPA, glufosinate, and 3-MPPA (0.5 ppm) spiked in both sample matrices were determined to be 72−81, 71−86, 101−119, and 83−90%, respectively, whereas the coefficient of variation was determined to be