Method for Gas Chromatographic Analysis of Fatty Acid Composition of Glycerides Containing Short-Chain Fatty Acids

Abstract

n-Propylester method was studied to establish a simple and convenient method for gas chromatographic determination of fatty acid composition of fats and oils, such as butter fat, containing both low and high molecular weight acids. The conditions of the preparation of propylesters were examined with the mixtures of butyric and capric acids. It was found that the following procedure was appropriate to prepare the propylesters for GLC analysis.0.25g of acids and 1.25g of alcoholysis reagent (0.3% sodium in n-propyl alcohol) were placed in a 100ml volumetric flask and the mixture was gently agitated at room temperature for 5 minutes. Then the flask was filled up with 20% aqueous solution of sodium chloride to separate ester, and after vigorous shaking the mixture was allowed to stand at 40°C. Propylesters were obtained with a small amount of propyl alcohol as an upper layer.This procedure was further applied to triglycerides containing low molecular weight acids and the results were satisfactory.