A quantitative structure–property relationship analysis of soot–water partition coefficients for persistent organic pollutants

Geometrical optimization and electrostatic potential calculations have been performed at the HF/6–31G⁎ level of theory for investigated persistent organic pollutants (POPs). A number of statistically based parameters have been obtained. Relationship between soot–water partition coefficients (log KSC) of POPs and the structural descriptors has been established by the multiple linear regression method. The result shows that the quantities derived from electrostatic potential Vs−¯ and Vs,max, together with molecular surface area (AS) and the energy of the highest occupied molecular orbital (EHOMO) can be well used to express the quantitative relationship between structure and log KSC (QSPR) of POPs. Predictive capability of the model has been demonstrated by leave-one-out cross-validation with the cross-validated correlation coefficient of 0.9797. Furthermore, the predictive power of this model was further examined for the external test set with the correlation coefficient of 0.9811 between observed and predicted log KSC, validating the robustness and good predictive ability of our model. Furthermore, in order to further investigate the applicability of these parameters derived from electrostatic potential in prediction of soot–water partition coefficient for organic pollutants, eleven polycyclic aromatic hydrocarbons (PAHs), eleven polychlorinated biphenyls (PCBs) and nine phenyl urea herbicides (PUHs) from other source have also been studied. The QSPR models established may provide a new powerful method for predicting soot–water partition coefficients (log KSC) of organic pollutants.

Quantitative relationship between soot–water partition coefficients (log KSC) and structural descriptors for investigated persistent organic pollutants (POPs) has been well established using the theoretical descriptors derived from surface electrostatic potentials, together with molecular surface area (AS) and the energy of the highest occupied molecular orbital (EHOMO). The predictive power of the model has been demonstrated by leave-one-out cross-validation and the external test set. Figure shows the relationship between the observed and predicted values from which good agreement is evident.Figure optionsDownload as PowerPoint slideHighlights
► A number of structural parameters have been obtained for persistent organic pollutants.
► Relationship between the structural parameters and soot–water partition coefficients was established.
► Robustness and predictive ability of the models has been demonstrated.
► Molecular surface electrostatic potentials have good applicability in QSPR.