A Modified Method to Estimate Total Carbonyl Compounds in Frying Oils Using 1-Butanol as a Solvent

Abstract

A modified method has been developed for quantitative determination of total carbonyl compounds in frying oils without using benzene. The analysis is done by the reaction of 2, 4-dinitrophenylhydrazine (2, 4-DNPH) with aldehydes and ketones in 1-butanol (1-BuOH) for 20 min at 40°C. The optimal wavelength to determine the total carbonyl compounds is 420 nm where the 2, 4-dinitrophenylhudrazone (2, 4-DNP) derivatives from saturated and unsaturated aldehydes and ketones have the same molar absorption coefficient. When the modified method was applied for the estimation of total carbonyl compounds in frying oils by using 1-BuOH instead of benzene as a solvent, a good correlation with the conventional method was obtained. It was expected that the modified method could be substituted for the conventional method and be useful for evaluating the quality of frying oils.