Fluorometric Method for Determination of 1,2-Unsaturated Aldehydes in Autooxidized Lipids with 2,4-Diaminotoluene

Abstract A simple fluorometric method has been developed to determine 1,2-unsaturated aldehydes in autooxidized lipids. 1,2- Unsaturated aldehydes were allowed to react with 2,4-diamlnotoluene in acidic condition and the products, 7-amlno-6- methylqulnoline derivatives, were determined by a fluorometric procedure at 394 nm (excitation wavelength) and 494 nm (emission wavelength). Finally, 1902.9, 1738.8, and 2149.2 μg/g of 1,2-unsaturated aldehydes as 2-propenal were detected in 20-h autooxidized methyl oleate, methyl llnoleate, and methyl llnolenate, which contained 98.5, 223.2, and 355.6 μg/g, respectively, of thlobarblturlc acid reactive substances as malondialdehyde. In a preliminary liquid chromatographic LC determination of 2-propenal In autooxidized lipids, 29, 20, and 57 μg/g, respectively, of 2- propenal were detected In 20-h autooxidized methyl oleate, methyl llnoleate and methyl llnolenate. The 2-propenal can be detected as 7-amlno-6-methylqulnoline by using LC-fluorometrlc procedure at levels of 100 pg.