Document Type

Article

Publication Date

4-1-2006

Abstract

Synthesis of glyceride esters of a fatty acid produces a mixture of isomers that are difficult to separate and analyze, requiring high temperature GC in most cases particularly for long-chain esters. In this paper, we present a fast estimation of the composition of the glyceride esters of lauric acid and glycerol (monolaurin, dilaurin, and trilaurin) by FTIR band shape analysis. The method uses the fact that the carbonyl stretching regions of the pure glycerides have differentband shapes, which implies any composite band of a mixture of glycerides may be resolved into the component peaks due to each glyceride. The carbonyl band region was fitted with five component peaks using a commercial peak-fitting program. The peak at 1745 cm-1 is characteristic of trilaurin whereas the peaks at 1740 cm-1 and 1731 cm-1 provide a unique height ratio for mono- and dilaurin. Calibration curves were prepared and a system of two equations may be solved to obtain the composition of mono-, di-, and trilaurin. This method was tested with known mixtures of the glycerides yielding estimates within ± 10 % composition units.

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