Characterization of Chlorinated Hydrocarbon Pesticide Metabolites of the DDT and Polycyclodiene Types by Electron Impact and Chemical Ionization Mass Spectrometry

Abstract

The electron impact and chemical ionization mass spectra for essentially all of the known metabolites, and a few proposed metabolites, and their derivatives of the chlorinated hydrocarbon pesticides, DDT, dieldrin, and aldrin (and their isomers) have been examined. The EI and CI spectra of these systems are in most cases qualitatively and quantitatively different, and, therefore, chemical ionization mass spectrometry adds a new dimension to the MS identification and characterization of these and related compounds as potential environmental agents. In addition, the chemical information derived from both the EI and C1 spectra is appreciable and valuable in studying the metabolism and other degradative processes of these compounds such as their photolysis and thermolysis. Not only was general chemical information obtainable from the mass spectra, but it was also possible to derive stereochemical information. A comprehensive study of this type has clearly demonstrated the combined advantages of E1 and CI mass spectrometry in differentiating closely related systems. Minimum detectability was not a major concern in these studies, but with the aid of multiple ion detection in conjunction with the qualitatively different EI and CI mass spectral patterns for these compounds, it should be possible to confidently identify amounts in the low nanogram or even in the picogram range.