ISSN 1017-2548(Print)
ISSN 2234-8530(Online)
Volume 37, Number 5
JKCSEZ 37(5)
October 20, 1993 

The purpose of this study was to investigate the retention behavior of phenols and to predict their retention in RPLC. The retention data of twenty-five phenols were measured on a μ-Bondapak C18 and a polymeric C18 columns with methanol-water and acetonitrile-water as a mobile phase. From the observation of enthalpy-entropy compensation phenomenon, the following conclusions are drawn with regard to the retention mechanism: 1) the retention mechanism of nitrophenols in different from that of metheyl-and chlorophenols in both mobile phase; 2) in methanol-water mobile phase, the retention mechanism of methyl-and chlorophenols is consistent in the range of methanol-water composition; 3) on the other hand, in the case of acetonitrile-water mobile phase, the retention mechanism depends on the volume fraction of acetonitrile. It means that the retention mechanism can not be explained only by a simple interaction. Based on retention data as compared with two columns, it may be said that the hydrophobic interaction of phenols with polymeric C18 column was greater than that with monomeric C18 column. The equations for predicting the retention of phenols were derived by using hydrophobic substituent constant (π) and the sum of Hammett's constant (σ) and Taft's steric constant (Es).