QUANTITATION OF NEUTRAL LIPID MIXTURES USING HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHY WITH LIGHT-SCATTERING DETECTION

A high performance liquid chromatographic (HPLC) method was developed for quantifying reaction mixtures obtained from the lipase-catalyzed t ransesterification of fats and oils. The reaction mixtures of interest were composed of neutral lipid classes that include alkyl esters, fre e fatty acids, triglycerides, 1,2- and 1,3-diglycerides, and 1 (2)-mon oglycerides. The method, a modification of a literature procedure, use s a binary mobile phase of hexane (A) and methyl-t-butyl ether (B) eac h modified with acetic acid (0.4%) and a gradient elution profile that reduced analyses' times by 25%. Lipid classes were measured by use of an evaporative light scattering detector (ELSD). Precision of injecti on and linearity of response of the ELSD over the range of sample amou nts of interest were established for the lipid classes measured by use of standards. The method was applied to the compositional analysis of prospective biofuel alkyl esters prepared from fats, oils, and recycl ed greases.