Novel classification to predict relative gas chromatographic retention times and n-octanol/water partition coefficients of polychlorinated biphenyls

By classifying on the basis of a novel descriptor, the number of adjacent chlorine atoms(Nad), a linear relationship was found between solvent accessible surface area(SAS) of tri-, tetra-, penta-, hexa-, and hepta-chlorinated biphenyls and experimental data such as relative gas chromatographic retention times(GC RRTs) and logarithm of n-octanoUwater partition coefficients(logKow). Both of the correlation coefficients between predicted and measured GC-RRTs and logKow markedly increased by utilizing the classification. For each PCB isomer, it was found that GC-RRTs tended to decrease with an increase in the twist angle between phenyl groups, and that the hydrophobic properties of PCBs were non-additionally enhanced with Nad.