INFLUENCE OF PHYSICOCHEMICAL PARAMETERS OF SOME RING-SUBSTITUTED PHENOL DERIVATIVES ON THEIR RETENTION ON A POROUS GRAPHITIZED CARBON COLUMN

The retention characteristics of 29 phenol derivatives were determined on a porous graphitized carbon column in unbuffered acetonitrile - water and methanol - water eluent mixtures at various organic phase concentrations. Each phenol derivative showed symmetric peaks in each eluent without buffers. Good linear correlations were found between the log k' value and the organic mobile phase concentration in the eluent. Principal component analysis indicated that methanol and acetonitrile expose different selectivities. Stepwise regression analysis proved that the retention of ring - substituted phenol derivatives is mainly governed by the sterical parameters, electron-withdrawing power and hydrogen donor capacity of substituents. According to the results of Free-Wilson analysis, the substituents with large steric parameters, strong electron-withdrawing power and hydrogen donor capacity have the highest impact on the retention. The lipophilicity of phenol derivatives did not affect significantly the retention, although the eluents were typical reversed-phase eluents.