Solute-solvent interactions from gas chromatographic activity coefficients and the solvation parameter model for nitrogen-containing stationary phases.
Infinite dilution gas-liquid chromatographic activity coefficients (gamma) and excess thermodynamic molar partial magnitudes [Gibbs energy (G(E)), enthalpy (H(E)), and entropy (S(E))] for 37 solutes of varied polarity on four stationary phases with -NH groups are obtained from partition coefficients taken from literature. Relationships between G(E) and S(E) with the 37 solutes' structure in terms of the molecular connectivity index ((1)chi(v)) are investigated. Correlations of solute-solvent interactions calculated in light of the solvation parameter model for selected solutes and stationary phases are tested. The effect of the solute's structure, expressed as the molecular connectivity index, on the nonpolar (cavity formation and dispersion interaction) [c+l. log L(16)] and the effect of the dipole moment and of the activity coefficient on the dipolarity-polarizability interaction (spi(2)(H)) are studied. The correlation between the nonpolar interaction with the athermal activity coefficient on the nonpolymeric stationary phases is also attempted. In addition, the influence of the stationary phase polarity on the solute-stationary phase interactions for a series of solutes is studied.
Santiuste
José M
JM
Instituto de Química Física "Rocasolano", CSIC, Department of Structure and Molecular Dynamics, C. Serrano, 119, 28006-Madrid, Spain.