Effect of alcohol chain length, concentration and polarity on separations in high-performance liquid chromatography using bonded cyclodextrin columns.
The effect of alcohol chain length, concentration and polarity on separation in high-performance liquid chromatography using beta-cyclodextrin-bonded silica is discussed. The results show that retention times cannot be predicted merely from the polarity of the binary mobile phase. Although organic modifiers with the same physico-chemical properties and from the same solvent group were used, the retention times obtained using binary mobile phases having the same polarity, were different. It was also observed that normal-chain carbon alcohols gave retention times shorter than those obtained with a branched-chain alcohol (n-propanol vs. isopropanol), and the longer the alcohol chain the shorter the retention times. A plot of ln k' vs. alcohol volume fraction for benzene, toluene, ethylbenzene, propylbenzene, butylbenzene, 1-phenylhexane and 1-phenyloctane gave a linear relationship in methanol, ethanol and propanol (except for 1-phenylhexane). A non-linear relationship was obtained for all the solutes in isopropanol, tert.-butanol and 1-butanol, in the alcohol volume fraction studied.
Atamna
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Program Resources, Inc., NCI-Frederick Cancer Research Facility, MD 21701.
Muschik
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Issaq
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D000433:1-Propanol / Q000494:pharmacology; D000438:Alcohols / Q000032:analysis* / Q000494:pharmacology; D000440:Butanols / Q000494:pharmacology; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D003505:Cyclodextrins; D003912:Dextrins; D000431:Ethanol / Q000494:pharmacology; D000432:Methanol / Q000494:pharmacology; D013213:Starch
D000438:Alcohols; D000440:Butanols; D003505:Cyclodextrins; D003912:Dextrins; D000431:Ethanol; D013213:Starch; D000433:1-Propanol; D000432:Methanol