Abstract: A sensitive analytical method was developed for the simultaneous determination of glyphosate, glufosinate and aminomethylphosphonic acid by capillary electrophoresis with laser-induced fluorescence detection (CE-LIF). 5-(4,6-Dichlorotriazinyl) amino fluorescein (DTAF) was successfully applied to label the herbicides. The optimal derivatization reaction was carried out in boric acid buffer of pH 9.5 at 30 ℃ for 40 min. The baseline separation of the three derivatives could be accomplished using 30 mmol/L boric acid, 15 mmol/L Brij-35 (pH 9.5) as the running buffer. The detection limits (S/N=3) for the glyphosate, glufosinate and aminomethylphosphonic acid were 3.21, 6.14, 1.99 ng/kg, respectively. Finally, the method was successfully applied to the analysis of environmental samples, and the three compounds were measured without any interference from real samples. The recoveries of the compounds in these samples were 91.3%~106.0%. The method has the advantages of easiness and sensitivity, and can meet the requirement of the determination of the herbicide and metabolite residues in the environmental samples.

Key words: derivatization, herbicides, laser-induced fluorescence detection (LIF), soil, water, capillary electrophoresis (CE)