Quantitative Analysis of the Mixture of Eugenol, cis- and trans-Isoeugenol by Gas-Liquid Chromatography with the Thermal Conductivity Detector

Abstract

This paper describes quantitative analysis of a mixture of eugenol, cis- and trans- isoeugenol by gas-liquid chromatography with the thermal conductivity detector using silicone D.C. 550, D.O.S., Apiezone L., P.E.G. 1500 and 4000, and D.B.P. as the liquid substrates. The following results were observed.Every liquid substrate was used individually or in combinations of two or three. In the latter cases, the substrates were utilized in a mixed manner and in repeated coating with each of two or three substrates, resulting in the finding upon analysis that D.C. 550 and D.O.S. (mixed) gave excellent results.Twenty four samples of substrates were examined for retention time in the gas chromatograms in comparison with those of eugenol and cis- and trans- isomers of isoeugenol. Among them, carvone, acetyleugenol, diethyl phthalate, n-propyl cinnamate and showed different retention time as compared with those of homologues of eugenol. Thus these substrates indicated as usable, as the inner standard material in the quantitative analysis of gas chromatography.Upon analysis, acetyl eugenol showed migration of the acetyl group to isoeugenol in the sample, resulting in acetylisoeugenol. Carvone and n-propyl cinnamate were found as preferable rather than diethyl phthalate because of less tailing and shorter retention time in gas chromatograms. But carvone was apt to scale out in gas chromatograms even when used in low weight-ratios for a sample measured.Quantitative analysis of the sample prepared (eugenol : cis-isoeugenol : trans- isoeugenol=29.8:33. 8:36.4) was carried out within relative experimental errors of ±1.5%, using n-propyl cinnamate as an inner standard material.No transformation was seen between cis- and trans- isoeugenol in these analyzing procedures.