The lipophilicity of parabens estimated on reverse phases chemically bonded and oil-impregnated plates and calculated using different computation methods.

The chromatographic behaviour of the parabens has been investigated on RP-18F(254S), RP-18WF(254S), CNF(254S), Diol F(254S) and silica gel 60F(254) plates impregnated with different oils (paraffin, olive, sunflower and corn) using methanol-water mixtures in different volume proportions as mobile phases, the regression determination coefficients being excellent (higher than 0.98 for the majority of compounds). Moreover, highly significant correlations were obtained between different experimental indices of lipophilicity (R(M0), b and scores corresponding to the first principal component (PC1)) and computed log P values. All types of stationary phases investigated appear to be highly suited for estimating the lipophilicity of the parabens.