Retention Behavior of Calixarenes with Various C₆₀ Bonded Silica Phases in Microcolumn Liquid Chromatography

Separation of the cyclic molecules, calixarenes, was performed by microcolumn LC using various chemically bonded C₆₀ silica stationary phases. The retention factors of tert-butylcalix[8]arene were higher with the C₆₀ bonded phases than those obtained with an ordinary octadecylsilica (ODS) phase under the same separation conditions. The separation of sulfonated calixarenes was also examined. The retention of these solutes was lower on C₆₀ bonded phases than on ODS. This retention behavior can be explained by the fit of the molecular shape of the solutes to the stationary phase ligand, e.g., lert-butylcalix[8]arene has a bowl-shaped cavity structure.