An automated transesterification technique for quantitation of acid precursors of ester-based oils.

A novel automated transesterification (ATE) technique has been developed for the quantitative determination of acid components used in synthesizing ester-based oils. The ATE technique has been successfully tested over a period of more than five years using several commercially available ester-based new and used refrigeration oils and jet oils. In this automated technique, the ester-based oil is transesterified using a commercially available SAP-Ester kit, and the resulting methyl ester mixture is then extracted and analyzed by gas chromatography (GC). During the transesterification, the large number (50-100) of oil-ester components are significantly reduced to a much smaller group of easily resolvable and quantitatable methyl esters (mostly < 6, depending upon the number of acids used).