To identify assays useful for quantitating epoxide lipid oxidation products, HBr titration of epoxides, nitrobenzylpyridine (NBP) reaction with colorimetric endpoint, diethyl dithiocarbamate (DETC) complexation with high pressure liquid chromatography (HPLC) separation and quantitation of adducts, and 1H nuclear magnetic resonance (NMR) were evaluated for accuracy, sensitivity, stoichiometry, and reproducibility using authentic epoxide standards. The HBr assay was too insensitive (detects 0.0075-0.1M) for quantitating lipid epoxides in foods and biological materials. The nitrobenzylpyridine assay detected 0.5 mM epoxides, but reaction response varied considerably with reaction conditions and increased with epoxide chain length, requiring different standards for each epoxide analyzed. The DETC reaction response was sensitive (1 mM to 1 mM) and HPLC separation of individual epoxides provides important information about oxidation chemistry. NMR detects micromolar epoxides, and clearly distinguishes epoxides from other oxidation products. The DETC-HPLC and NMR assays hold the greatest promise for routine analysis of epoxides in oxidized lipids.

Evaluation of HBr, nitrobenzyl pyridine, diethyl dithiocarbamate, and <sup>?1</sup>NMR methods for quantitating lipid epoxides

246th National Meeting (2013)

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Evaluation of HBr, nitrobenzyl pyridine, diethyl dithiocarbamate, and ?1NMR methods for quantitating lipid epoxides

Evaluation of HBr, nitrobenzyl pyridine, diethyl dithiocarbamate, and ^?1NMR methods for quantitating lipid epoxides