Enrichment of Trace Chlorinated Species in a Complex Matrix of Fatty Acids Using HPLC in Conjunction with Gas Chromatography‐Halogen Specific Detection

Abstract

Due to the similarity in chemical and physicochemical properties between analytes (chlorinated fatty acids) and matrix compounds (nonchlorinated fatty acids), conventional cleanup procedures were not successful in analysis of chlorinated fatty acids in extracts of freshwater fish. A new approach was devised of utilizing reversed‐phase high performance liquid chromatography (HPLC) for its high separation power, and the halogen specific detector (XSD) for its high selectivity for organochlorine. The bulk of nonchlorinated matrix was removed by HPLC fractionation, and target chlorinated analytes were selectively enriched. The enrichment effect was assessed by a universal detector, a flame ionization detector (FID). Methyl esters of chlorinated fatty acids were completely nondetectable prior to HPLC fractionation, but were present as moderate or small, yet discernible, peaks after the HPLC enrichment. This enrichment method is efficient with good selectivity, reproducibility, and predictability.