A,C- and A,D-bridged calixarene
capillary gas chromatography
geometric and positional isomer separation
Analytical Chemistry and Spectroscopy
Wiley InterScience Backfile Collection 1832-2000
Chemistry and Pharmacology
---A,C-Bridged (ACCX) and A,D-bridged isopropyldimethylsilylcalixarene (ADCX) dissolved in OV-1701 were used as stationary phases in isothermal capillary gas chromatographic separation of some positional isomers. Retention factors and separation factors for the isomers were measured. The isomers investigated are well resolved on the two phases. Retention of all the solutes investigated is longer on ACCX than on ADCX. The longer retention on A,C-bridged calixarene is probably due to extra inductive interactions of the solute molecule with the carbonyl moieties in the phase. Separation factors for closely eluting isomer pairs are similar on the two phases. This seems to indicate that the carbonyl moieties do not play an appreciable role in discriminating the isomer molecules on entering the cavity of the calixarene if the solute is retained by the inclusion process.
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