Determination of octanol-water partition coefficients of polar polycyclic aromatic compounds (N-PAC) by high performance liquid chromatography

Prediction of 1-octanol water partition coefficients for a range of polar N-PAC from HPLC capacity coefficients has been investigated. Two commercially available columns, an ODS column and a Diol column were tested with water-methanol eluents. The best prediction of log Kow for N-PAC was achieved using a Diol column with an eluent of 35% MeOH and 65% water. The results indicate that the Diol column, in reversed phase mode, is able to form hydrogen bonds with a solute. Different LFERs between retention and log Kow was found for polar and nonpolar compounds. In general log Kow increased with size and log Kow for N-PAC was 1.1-1.3 lower than log Kow for the equivalent PAH. Shielding of the nitrogen atom in the N-PAC compounds caused an increase in log Kow.