Determination of octanol/water partition coefficients for long-chain homologs of orcinol from cereal grains.

Polycratic reversed-phase high-performance liquid chromatography (RPHPLC) was used for estimation of the octanol/water partition coefficient for three highly hydrophobic long chain orcinol homologs. The homologs studied (C 15:0, C 17:0 and C 19:0) showed high preference for hydrophobic phase as evidenced by their high octanol/water partition coefficient (log Po/w) values of 7.02-7.74; 8.71-9.47 and 10.49-11.32 for the 95% prediction interval, respectively. Experimentally estimated values were compared with log P values calculated with the use of several fragmental systems. The experimental values of log Po/w are in best agreement to those calculated with the use of the Klopman system (Klopman, G., Namboodiri, K. & Schochet, M., 1985, J. Comput. Chem. 6, 28-38). The lack of appropriate standard compounds with known log Po/w in the range over 6 markedly affected the accuracy of experimental determinations.