Factors Affecting Recovery of Methyl Esters of Short-Chain Fatty Acids from Esterification Mixtures

Abstract

A modified method for esterification of free fatty acids and extraction of their methyl esters for subsequent analysis by gas-liquid chromatography has been standardized. The recovery of the short-chain esters was improved by techniques known to favor more complete extraction of organic materials from an aqueous phase. Saturation of the aqueous phase with NaCl prior to extraction of the esters increased the recovery of methyl butyrate from about 30 to approximately 65% when 0.5 ml of petroleum ether was used for extraction. The recovery of methyl butyrate was increased further to about 95% by use of an optimum solvent: water ratio during the extraction step.