Colorimetric Microdetermination of Free Fatty Acids

Abstract

Abstract A colorimetric method for determination of free fatty acids has been developed, based on the estimation of copper in a chloroform extract of their cupric salts with oxalic acid bis-(cyclohexylidenehydrazide). Contamination with inorganic copper during extraction is practically eliminated by using filter-paper pads. Specificity and interferences are discussed. Recoveries average 101.1%. Normal values are 10.0 ± 8.2 mg/dl (0.390 ± 0.320 mmol/liter), with no statistically significant sex-related difference. Correlation with the reference method of Dole and Meinertz [J. Biol. Chem. 235, 2595 (1960)] is 0.954. Ten samples can be measured in about 45 min.