Multiresidue determination of Endosulfan and metabolic derivatives in human adipose tissue using automated liquid chromatographic cleanup and gas chromatographic analysis

A multiresidue method based on normal-phase liquid chromatography (LC) cleanup and gas chromatography-electron capture detection-mass selective detection (GC-ECD-MSD) analysis has been developed for the determination of endosulfan and its main metabolic derivatives in human adipose tissues. Analytes were extracted by dissolving the fat samples in n-hexane, and the hexanic extracts were directly injected onto the silicagel column of the automated LC cleanup system. Purified LC extracts were analyzed by GC-ECD or GC-MSD, without any solvent exchanges or preconcentration steps. The high efficiency of the high-performance liquid chromatographic cleanup for the elimination of fats allowed to reach detection limits for all analytes at low nanograms-per-gram concentration levels. The optimized overall analytical procedure was applied to 18 selected human mammary adipose and abdominal fat tissue samples, p,p′-DDE, hexachlorobenzene, and β-HCH were the most frequently detected compounds, and residues of endosulfan -sulfate and -ether were also found in several samples. All findings were confirmed by an additional GC-MS-MS analysis of the LC sample extracts.