Determination of Products of Lipid Oxidation by Infrared Spectroscopy

Lipid peroxidation is initialed as activated oxygen reacts with the double bonds on the lipid hydrocarbon chains (1 ). Depending on the type of lipid, type of oxidant, and severity of the oxidation, a variety of lipid-peroxidation products are formed (1 ). The major proucts of lipid peroxidation are moieties containing hydroxyls, hydroperoxyls, aldehydes, ketones, caroxylic acids, and trans double bonds. Infrared spectroscopy is a sensitive technique that can detect all of these groups and is uniquely sensitive in detecting hydroxyl and hydroperoxyl groups (2 –8 ). The detection of lipid hydoxyl and hydroperoxyl groups is especially useful for quantifying the oxidation of mono unsaturated lipids, such as those found in the ocular lens, where secondary products of lipid oxidation such as malondialdeyde are not readily formed (9 ,11 ).