have been developed to detect and measure biological The oxidation of lipids, lipid peroxidation, is usually lipid peroxidation such as the thiobarbituric acid assayed with thiobarbituric acid (TBA). We compare (TBA) 2 test, diene conjugation, fluorescence, light emisthe TBA assay measuring TBA-reactive substances sion, spin trapping, cyclooxygenase, oxygen electrode, (TBARS), and a new gas chromatography-mass speciodine liberation, glutathione peroxidase, heme degratrometric (GC-MS) assay measuring malondialdehyde dation of peroxides, high-performance liquid chroma-(MDA) with unsaturated fatty acids and biological tography/antibody techniques, hydrocarbon gases, and samples. The extent of oxidation to different unsatugas chromatography-mass spectrometry (GC-MS) (3rated fatty acids is related to the total number of bis-6). Among these methods, the most widely used, and allylic positions, the position of the first double bond also criticized technique, is the TBA test, in which the from the methyl terminus, and the lipid chain length. test sample is heated in acid buffer with TBA and the The extent of oxidation of different biological samples resulting pink chromogen is measured by absorbance or organs is related to the component polyunsaturated at 532 nm or by fluorescence (excitation 515 nm and fatty acids. Both the GC-MS and TBA assays give paremission 553 nm) because of the unique electronic aballel results for oxidation of unsaturated fatty acids sorption spectrum of the adduct formed. Malondialdeand biological samples. The GC-MS assay is about twohyde (MDA), one of several low-molecular-weight end