Identification of cholesterol as a possible interference in the analysis of fish tissue for industrial chemical residues.

The presence of cholesterol in cleaned up fish tissue extracts has been established by gas-liquid chromatography and confirmed by mass spectrometry. It was found both in extracts cleaned up by gel permeation chromatography and in those extracts prepared by the AOAC method for nonfatty foods. It is not normally observed in routine residue analyses because selective gas chromatographic detectors such as electron capture are commonly used.