Determination of log P by dispersive liquid/liquid microextraction coupled with derivatized magnetic nanoparticles predispersed in 1-octanol phase.

A new direct method for log P determination by dispersive liquid/liquid microextraction (DLLME) coupled with derivatized magnetic nanoparticles (DMNPs) predispersed in 1-octanol phase is discussed. First, the aim of DMNPs predispersed into 1-octanol phase was to provide the magnetic force when an ultrastrong magnet was used to separate the two phases. Second, the interaction of 1-octanol with inner DMNPs nuclei prevented emulsion formation in the DLLME process. Moreover, interruption of absorption of DMNPs due to the partition equilibrium of the model compound was negligible. The equilibrium of model compound between the two phases was reached in less than 3 min. The two phases were separated quickly by a super magnet because model compounds in the two phases did not interfere with each other. Fourteen model compounds of varied log P values were measured using this method. The log P values fall in the range of 0.6 to 4.8, which are in agreement with the published results. This method is a rapid, efficient and facile method for direct measurement of log P values.