A new LC/APCI-MS method for the determination of cholesterol oxidation products in food

Cholesterol oxidation products (COPs) can be formed in the body or in animal foods from cholesterol during food processing. A new method for the extraction and quantification of cholesterol, 7-ketocholesterol, cholestane-3 beta-5 alpha-6 beta-triol, 25-hydroxycholesterol, 5,6 alpha-epoxycholesterol, and 7 beta-hydroxycholesterol by means of reversed-phase LC/atmospheric pressure chemical ionization mass spectrometry is presented. A baseline separation of all COPs was achieved, allowing a separate quantification also for isobaric compounds. The limits of detection were 15-30ng/mL, quantification was performed from 100ng/mL to 10 mu g/mL with RSD < 2%. The method was applied successfully to the determination of cholesterol and COPs in processed foods such as pork, beef, chicken, and egg. (c) 2004 Elsevier B.V. All rights reserved.