Derivation of solubility parameters of chlorinated dibenzofurans and dibenzo[p]dioxins from gas chromatographic retention parameters via SOFA

Molar heat of vaporization, molar liquid volume and Scatchard-Hildebrand solubility parameters of chlorinated dibenzofurans (PCDFs) and dibenzo[p]dioxins (PCDDs) were derived from (semi-)empirical values of heat of vaporization, (subcooled) liquid density and gas chromatographic Kovats retention indices. To this end a thermodynamic prediction model (SOFA), recently developed, was extended by an exchange entropy contribution representing molecular orientational disorder. The parameters derived were validated using experimental values of relative retention times on stationary phases of different polarities. Accurate to extremely accurate results were obtained with standard errors of regression close to experimental inaccuracy and high correlation coefficients comparing favourably to existing methods of prediction. The parameters derived performed quite well for apolar to moderately polar stationary phases. For polar phases inaccuracy increased significantly. The method has several advantages compared to other methods used for the prediction of chromatographic retention.