The analysis of 25-hydroxycholesterol in plasma and cholesterol-containing foods by high-performance liquid chromatography.

A method for the analysis of 25-hydroxycholesterol by high-performance liquid chromatography (HPLC) in a wide range of materials is described. Lipid extracts were initially purified on octadecyl silicic acid cartridges and by reversed-phase HPLC before quantitation by HPLC on a silicic acid column. The reproducibility of the method was confirmed by the analysis of plasma from rats fed 25-hydroxycholesterol. 25-Hydroxycholesterol was not detected in lard, cream, fresh egg yolk or spray-dried egg yolk powder. It was detected in egg yolk powder after heating at 110 degrees C for 4 days and its authenticity was confirmed by mass spectrometry.