STRUCTURALLY INFORMATIVE RESPONSE PATTERNS OF SOME MONOTERPENOIDS FOUND IN VOLATILE OILS TO GAS-CHROMATOGRAPHY ON 2 COMMERCIAL DIPENTYLATED CYCLODEXTRIN PHASES

Gas chromatographic retention times relative to n-undecane at 100-150-degrees-C were plotted for various monoterpenoid alcohols or carbonyl compounds on two ''Chiraldex'' depentylated cyclodextrin phases. As the temperature was increased, the modified beta-cyclodextrin (''B-DA'') just showed all values decreasing. However, the alpha-cyclodextrin (''A-DA'') exhibited distinctive solute patterns. 4- and 1-ols and aldehydes typically gave a decrease again, but 3-ols and 3-ones exhibited near constant values, whilst the relative retention times of 4-ones (especially bicyclic ones) increased. This smaller ring ''Chiraldex'' responded to the position of the polar group in the solute molecules, whilst the larger ring reacted to the rigid bulk of the molecules. Increases in results with change to the larger ring phase B-DA were over 70% at 125-degrees-C for bicyclics, exactly 28% at 150-degrees-C for three different dienes, and low or even negative for acyclic tepenoids like citral. Such results could indicate structural information about unidentified terpenoids.