Structure‐retention correlation in CGC

Abstract

SummaryThe retention time of 24 alkanes (Al-Al), 11 olefins (OI), 17 alkyl alcohols (AI-OH), 30 fatty acid methyl esters (FA) and 8 polyaromatic hydrocarbons (PAH) was measured on non-polar CP-SiI-5 and DB-1 and polar CP-WAX-52 and DB-WAX capillary columns at different temperatures.The correlation coefficients of the capacityratiosof each groupof compoundsand that of all the compounds togetherwasexcellent; however, there was some selectivity of different types of compounds when their capacity ratios were correlated with their Van der Waals volumes. The elution order of these compounds was AI-AI < 0 1 < FA < AI-OH < PAH on both non-polar columns, while the retention of PAH was greater on the DB-1 column and those of other compounds were greater on the CP-Sil-5-column. Such selectivity was significant on polar columns.Further, the energy effect, which was used to make a retention index system in liquid chromatography, was obtained from their capacity ratios to make a retention index system for capillary column gas chromatography. The values of the energy effect of each group of compounds were quite constant compared to the values obtained in liquid chromatography.The selectivityof these capillary columns was further discussed from their capacity ratios, their Kovats retention indices, and their energy effect to make a prediction of retention time.

Gas chromatography

“…Several broadly significant studies on the relationship between solute structure and retention on a particular liquid hase were published by Hanai (01, 02) who provided a m o t h for enthalpy and selectivity and a correlation between van der Waals volumes and capacity ratios. van der Waals volumes were also utilized in structural models for describing retention of alkyhaphthalenes (03).…”