Characterization of Calixarene/Ionic Liquid Mixture as Gas Chromatographic Stationary Phase through Thermodynamic Parameters and LSER

摘要

A mixture of 5,11,17,23-tetra-tert-butyl-25,26,27,28-tetraethoxycarbonylmethyloxy calix[4]arene (C[4]TECM) and 1-octyl-3-methylimidazolium tetrafluoroborate ionic liquid (O_mI_m+BF₄ −) has been employed as stationary phases in capillary gas chromatography. Its properties have been characterized through thermodynamic parameters and linear solvation energy relationship. The experimental results showed that C[4]TECM–O_mI_m+BF₄ − mixture as gas chromatographic stationary phase has high column efficiency and peak symmetry, which were evaluated using naphthalene and n-octanol, respectively. It was demonstrated that the interaction forces between the probe molecules and the stationary phase did not change over the entire temperature range studied due to an excellent linear relationship between lnk and 1/T, the retentions of the probe molecules on the C[4]TECM–O_mI_m+BF₄ − stationary phase are enthalpy-driven processes, and the interactions of the probe molecules with C[4]TECM–O_mI_m+BF₄ − stationary phase mainly include hydrogen bonding interaction, dipole–dipole interaction and dispersive interaction. However, the contribution of each interaction is in the order of A > L > S for the C[4]TECM–O_mI_m+BF₄ − stationary phase.