Colorimetric micro-determination of free fatty acids in plasma

Abstract

A colorimetric micromethod, based on the formation of FFA-Cu soaps, was developed for determining free fatty acids (FFA) in 50 μl of plasma. FFA was extracted with chloroform-heptane-methanol. Silicic acid was used to eliminate interference by the phospholipids. Diphenylcarbazide was chosen for the colorimetric determination of copper. These modifications render the method more sensitive than other available colorimetric methods. The method requires only capillary samples and is therefore suitable for repeated registration of the concentration of FFA during experimental conditions.