Theoretical Analysis on Retention Behavior of Phenols in Inversed-phase High Performance Liquid Chromatagraphy

The geometries of phenol, hydroquinone, resorcinol, catechol, o-aminophenol, p-nitrophenol and 2,4,6-trinitrophenol were optimized using ab initio Hartree-Fock and density functional theory B3LYP method at 6-31G(d) level. The molecular radius and molar volume in gas, the dipole moment in gas, water and methanol, the sum of negative Mülliken charges and the frontier molecular orbital (LUMO and HOMO) were also calculated at the same level. Seven phenol compounds were separated by inversed-phase high performance liquid chromatography (HPLC). The correlation coefficient of retention time the molecular radius or molar volume, the dipole moment, the sum of negative Mülliken charges and LUMO are more than 0.9957 using multiple linear regression (MLR). The results show that the retention time of solute in HPLC is controlled by the molecular radius or molar volume, the dipole moment, the sum of negative Mülliken charges LUMO and the interaction between solution and solute.