Relationship between retention characteristics and physicochemical parameters of solutes on porous graphitized carbon column

The retention of 44 barbituric acid derivatives was determined on porous graphitized carbon (PGC) column using dioxane-water mixtures as eluents. Linear correlations were calculated between the logarithm of the capacity factor and the dioxane concentration in the eluent. Free-Wilson analysis combined with stepwise regression analysis was used to elucidate the role of individual substituents in the retention behaviour. Calculations indicated that the apolar substituents lie parallel to the surface of PGC surface increasing in this manner the retention and-as opposed to the retention characteristics of traditional reversed-phase supports-the position of substituents also exerts a marked influence on the retention. (C) 1998 Elsevier Science B.V. All rights reserved.