Temperature effects in the calculation of equivalent chain length values for multiple-branched fatty acid esters and ketones on polar and non-polar open tubular columns

Abstract

Accurate equivalent chain length (ECL) values were determined for methyl esters of a variety of methyl-branched fatty acids. Only those with methyl substituents in the C 2, C 3 and ω 1 (iso) position were particularly affected by changes in operating temperature on one type of polar open-tubular column, or were otherwise significantly affected by the polarity of different polyester columns. In other positional isomers ECL values dropped only very slightly with increasing temperature. On Apiezon L columns only the C 2 isomer was significantly affected. Adjustments for temperature effects improved accuracy in calculating ECL values for multiple methyl-branched fatty acids and some corresponding ketones.