Terpenoids : LXXXV. Evaluation of polyesters as stationary phases in GLC columns

Abstract

Polyesters from diferent 1,ω-glycols, ranging from ethylene glycol to 1,15-pentadecanediol, with adipic acid were prepared and evaluated as substrates for gas-liquid chromatography. Several terpenic and a few non-terpenic compounds were analysed. It was observed that the retention time is a characteristic of the number of methylene groups in the glycolic fragment of the polyester and, as before, follows a linear relationship, which starts deviating at 1,10-decanediol. The effect on retention times by using ethylene glycol and changing the acid fragment was also studied. Similarly, the effect on retention times by using 1,5-pentanediol (which has the same number of polyvalent atoms in the chain unit as diethylene glycol) and changing the acidic fragment was also examined. From the above mentioned observations, it was clear that the retention times of hydrocarbon-type compounds may be enormously increased by using a polyester derived from very-long-chain dicarboxylic acid and long-chian, 1,ω-glycol. However, the retention times of hydrocarbons reach a certain saturation point above which their solubilities do not increase appreciably. Finally, the effect of dead volume of the column was discussed with respect to the case of long-chain as well as short-chain polyesters. Some of the stationary phases described in the paper are likely to be very useful for capillary columns and for preparative gas-liquid chromatography.