Condensation nucleation light scattering detection with ion chromatography for direct determination of glyphosate and its metabolite in water

An ion chromatography–condensation nucleation light scattering detection (IC–CNLSD) method was successfully used to directly analyze glyphosate, a polar pesticide, and aminomethylphosaphonic acid, the major metabolite of glyphosate, in water without need of pre-treatment or derivatization. CNLSD gave a LOD of 53 ng/ml for glyphosate, which is much lower than the maximum contaminant level of 700 ng/ml for drinking water issued by the US Environmental Protection Agency. Spiked analytes in different matrixes were tested. A diluted commercial herbicide containing glyphosate was also evaluated. Compared to other reported methods, the IC–CNLSD method has no need of sample derivatization, pre-concentration, and mobile phase conductivity suppression. It is simple, fast and inexpensive. IC–CNLSD is an ideal direct detection technique for such pesticides without chromophores or fluorophores.