Partition coefficients of ionizable compounds in o-nitrophenyl octyl ether/water measured by the potentiometric method.

The objective of this study was to investigate the reliability of potentiometric measurements of partition coefficients (log P) in the o-NPOE/water system, o-nitrophenyl octyl ether being an organic solvent widely used for the voltammetric determination of the partition coefficient of ions. Three sets of ionizable model compounds were explored in this study. The results showed that the potentiometric technique gave precise and reliable log P(npoe) values in the explored range of 0.1-4.3.