- P-ISSN 1225-0163
- E-ISSN 2288-8985
Chromatographic retention mechanism of seven benzoic acids in RPLC were investigated. Inorganic salt is pertinent for the measurement of dead time in benzoic acid. Logarthims of capacity factor (log k') and Hildebrand solubility parameter (<TEX>${\delta}$</TEX>) showed proportional relationship which imply the hydrophobic effect of the retention mechanism in RPLC. Enthalpies of solute transfer showed inverse proportion to temperature and organic modifier ratio of the mobile phase. It was found that the S value showed positive slope in plot of log k' vs. volume fraction of water in mobile phase. Free energy change increases with increasing organic volume fraction. The hydrophobicity index, <TEX>${\varphi}_0$</TEX>(organic volume fraction) is inversely proportional to column temperature.