Fluorogenic labeling of organophosphate pesticides with dansyl chloride. Application to residue analysis by high-pressure liquid chromatography and thin-layer chromatography.

The analysis of some organophosphorus pesticides by fluorogenic labeling with dansyl chloride (5-dimethylaminonaphthalene--l-sulfonyl chloride) was investigated. The pesticides were hydrolysed in sodium hydroxide to the corresponding phenols. The reaction of dansyl chloride with the phenols was accomplished in a two-phase system. The resulting fluorescent derivatives were separated and analysed quantitatively by in situ thin-layer chromatography (TLC) and high-pressure liquid chromatography (HPLC). As little as 10-25 ng/spot of pesticide was detected by both TLC and HPLC.