GAS-LIQUID-CHROMATOGRAPHY IN QUALITATIVE-ANALYSIS .18. STUDY OF THE DEPENDENCE OF THE RETENTION BEHAVIOR OF POLYOXYETHYLENE GLYCOL COLUMNS ON THE NATURE OF THE SUPPORT AND PHASE LOADING

The retention behaviour of fourteen solutes, possessing a wide range of polarity, and five n-alkanes was investigated using various percentage loadings ofpolyethylene glycol 400 as stationary phase on two diatomaceous supports of different adsorptivity. Retentions were measured as Kováts retention indices and specific retention volumes, in order to compare the dependences of absolute and relative retentions on phase loading. For all the solutes examined the values of the retention index decrease with a reduction in phase loading, suggesting a decrease in phase polarity. In contrast, the polar test solutes display slight increases in specific retention whereas those of the n-alkanes increase enormously as the phase loading is decreased and thereby giving rise to the observed large shifts in retention index. In order to explain the phase loading dependence of retention index with polar stationary phases an elution mechanism involving a significant contribution of gas-liquid interfacial adsorption is proposed. © 1990.