Flame Ionization Detector Response Factors Using the Effective Carbon Number Concept in the Quantitative Analysis of Esters

FID response factors for 130 organic acid esters, such as ethyl-, isopropyl-, η-propyl-, isobutyl-, and η-butyl esters of C 1- C 2 0 fatty acids, C 2- C 1 2 aliphatic dicarboxylic acids, and those of benzoic- and o-phthalic acids have been given. On the basis of multiple measurements, the mean response factor of 10 reference compounds, covering the elution range of esters to be investigated, was determined with a relative standard deviation of 1.4%. The effective carbon numbers (ECNs) of various esters are reported with a relative standard deviation of 5.8 % or less. The contributions of various ester groups to the ECNs of C 1- C 2 0 fatty acids, C 2- C 1 2 aliphatic dicarboxylic acids, and benzoic and o-phthalic acids were calculated. The values obtained were as follows: 1.10,1.27, and 1.07 for the ethyl esters; 1.73,1.98, and 1.32 for the isopropyl esters; 2.23, 2.43, and 2.48 for the η-propyl esters; 3.23, 3.53, and 3.30 for the isobutyl esters; and 3.34, 3.67, and 3.28 for the n-butyl esters, respectively.