Simultaneous Determination of Glyphosate,Glufosinate, and Aminomethylphosphonic Acid by Capillary Electrophoresis After 9‐Fluorenylmethyl Chloroformate Derivatization

A capillary electrophoresis (CE) with UV absorption detection method is described for the simultaneous determination of glufosinate, glyphosate, and aminomethylphosphoric acid. The 9‐fluorenylmethyl chloroformate (FMOC‐Cl) was used for precolumn derivatization of the non‐absorbing herbicides. The three analytes were separated by CE in 9 min with 25 mM borate buffer at pH 9, followed by detection with a UV detector at 260 nm. We demonstrate how the detection limit can be enhanced by using acetonitrile‐salt mixtures. With acetonitrile‐salt mixtures, the limit of detection (LOD) was in the 10^?7 M range. Linearity of more than two orders of magnitude was generally obtained. Precisions of migration times and peak areas were less than 0.9% and 7.5%, respectively. The applicabilities of the method for the analysis of ground water and lake water were examined.