Dynamic Fluorogenic Labelling of Pesticides for High Performance Liquid Chromatography: Detection of N-Methylcarbamates with o-Phthalaldehyde

A post-column fluorogenic labelling reaction between o-phthalaldehyde (OPA) and methylamine, a hydrolysis product of the N-methylcarbamate and carbamoyl Florida Agricultural Experiment Station Journal Series No. 654. oxime pesticides, is described which provides a highly sensitive and selective detection mechanism for the high performance liquid chromatography of these pesticides. Separations were achieved by reverse phase, with solvent programming of water-dioxane mixtures. As little as 1 ng of the pesticides could be detected, with the last eluting carbamate, mesurol, requiring from 22 to 54 minutes, depending upon column and program contour. Chromatography was performed with a modular instrument and with a commercially available fully cabineted instrument.