Gas chromatographic–mass spectrometric identification of chlorinated octadecanoic acids in eel lipids

Abstract

Abstract Gas chromatographic (GC) studies with halogen‐selective electrolytic conductivity detection (ELCD) showed that chlorinated carboxylic acids are major organochlorine compounds in lipids of eel ( Anguilla anguilla ) from the receiving waters of a chlorine bleaching sulphite pulp mill. To facilitate the recording of full mass spectra, chlorinated carboxylic acid methyl esters were cold‐trapped after capillary GC separation monitored with ELCD. Methyl dichlorooctadecanoate was identified using GC/mass spectrometry (GC/MS) with both electron impact (EI) and ammonia positive‐ion chemical ionization (PICI). Methyl tetrachlorooctadecanoate was indicated by GC/EIMS. Each chlorinated fatty acid was observed at two retention times, suggesting the presence of isomers. The original fatty acid methyl esters derived from the eel lipids were subjected to GC/MS in the selected‐ion monitoring mode; methyl dichlorooctadecanoate was detected using PICI and methyl tetrachlorooctadecanoate was detected using EI ionization.