Evaluation of the Chromatographic Performance of di-and tri-amide Calix[4]arene Derivatives Bonded Silica Stationary Phases

The chromatographic behaviors of di- and tri-amide derivatives of calix[4]arene immobilized onto aminopropyl silica gel (Calix-SP1 and Calix-SP2) were evaluated by using some aromatic hydrocarbons and aromatic amines in the HPLC. The effect of organic modifier content, pH and column temperature on retention and selectivity of these compounds were investigated. The results of the study of column temperature influence have shown a high linear correlation between the logarithm of capacity factor and reciprocal value of absolute temperature for each studied analyte. The thermodynamic parameters implicated in chromatographic retention were determined using the van't Hoff method. The retention mechanism was also discussed. The results indicated that the stationary phases behave like a reversed-phase packing. However inclusion, hydrophobic, hydrogen bonding, and pp interactions seem to be involved in separation process.