Chlorinated fatty acids in lipid class fractions from cardiac and skeletal muscle of Chinook salmon

Analysis of chlorinated fatty acids (CFA) in tissues can be difficult because of their low concentrations. This task becomes even more difficult when samples are from organisms living in remote locations with very little exposure to environmental contamination. Therefore, enrichment of CFA is necessary prior to analysis. In this study, CFA were enriched from fractionated lipid classes of cardiac and skeletal muscle of Chinook salmon (Oncorhynchus tshawytscha) to determine CFA distribution among lipid classes and tissue types and to demonstrate the sensitivity of this method to detect CFA at trace concentrations. The lipids extracted from cardiac and skeletal muscle of O. tshawytscha were separated into fractions containing TAG, FFA, and phospholipids. After transesterification, the FAME derivatives from each lipid class were analyzed by GC with a halogen-selective detector (XSD) to determine the concentrations of dichlorostearic acid and dichloropalmitic acid. Other chlorinated compounds detected byGC-XSD were analyzed by GC-MS. CFA were observed in all lipid classes in both cardiac and skeletal muscle tissues. However, the highest concentrations of CFA were found in the phospholipids of both tissue types, about 1-2 mg/g lipid. It was also shown that dichloropalmitic acid concentrated in cardiac phospholipids whereas dichlorostearic acid was found primarily in the phospholipids of skeletal tissue. CFA concentrations in TAG and FFA fractions were below 150 mg/g lipid. This study demonstrates a small-scale approach to the study of CFA at trace concentrations and their distribution among lipid classes.