N-CHLOROALDIMINES .4. IDENTIFICATION IN A CHLORINATED MUNICIPAL WASTE-WATER BY GAS-CHROMATOGRAPHY MASS-SPECTROMETRY

N-Chloroaldimines are formed in aqueous solution by chlorination of nonpolar alpha-amino acids with greater-than-or-equal-to 2 equiv of aqueous chlorine at pH 7. Four N-chloroaldimines were identified in chlorinated municipal wastewater with varying degrees of confidence. The compounds were isolated from wastewater by ether extraction and concentrated by Kuderna-Danish evaporation before GC/MS analysis. The presence of N-chloroisobutyraldimine (I), a product of the chlorination of valine, was confirmed in two municipal wastewaters (primary effluents) by comparison of its retention time and EI and CI mass spectra with those of standards. The identity of N-chloro-3-methylbutyraldimine (II, from leucine), N-chloro-2-methylbutyraldimine (III, from isoleucine), and N-chlorophenylacetaldimine (IV, derived from phenylalanine) in the wastewaters was confident based on a comparison of retention times and CI mass spectra. However, the chromatographic peaks were too small to obtain EI spectra clear enough to make a confirmed assignment. The identity of IV was tentative since its presence was indicated by its retention time and CI spectrum in the multiple-ion detection mode and was only suggested on a second instrument in the EI mode.