Electron Donor-Acceptor Complexing Reagents for the Detection of Pesticides on TLC

Abstract
The formation of π-complexes to detect and identify a representative group of carbamate, anilide and urea pesticides was investigated. Results obtained with several electron-acceptor reagents used by previous workers are compared with those obtained with a group of nitro-substituted fluorene derivatives. The pesticides studied were chosen for their potential ability to act as electron donors. Detection limits after thin-layer chromatography ranged from 0.5 to 5.0 micrograms, depending upon the strength of the complex formed. Various chromatographic systems were studied and applications of in situ reflectance spectroscopy and mass spectrometry were investigated. The method combines a reasonable sensitivity with good selectivity and the pesticide may be recovered from the complex for further study. This non-destructive method of analysis should be of particular use in the separation and identification of these pesticides and their metabolites.