Determination of n-octanol–water partition coefficients by hollow-fiber membrane solvent microextraction coupled with HPLC

Abstract

A novel direct method has been developed for determination of n-octanol-water partition coefficients by hollow-fiber membrane solvent microextraction (HFMSME) combined with high-performance liquid chromatography (HPLC). The compound of interest is dissolved in water with sonication and a hollow fiber containing octanol inside is placed in the sample solution to perform microextraction. After microextraction the concentrations in both the aqueous and n-octanol phases are analyzed by HPLC with UV detection. The method was evaluated with ten reference compounds and shown to be suitable for determination of the partition coefficients of organic compounds accurately, cheaply, simply, and quickly. Previously unknown n-octanol-water partition coefficients have been obtained for other compounds by use of the hollow-fiber membrane solvent-microextraction technique.

Development of negligible depletion hollow fiber membrane-protected liquid-phase microextraction for simultaneous determination of partitioning coefficients and acid dissociation constants

“…Though various methods have been developed for the determination of K OW [3] and pK a [4] values, alternatives for high efficient determination of these parameters are still of interests. New approaches by using magnetic nano-absorbent [5], and twophase hollow fiber-based liquid-phase microextraction procedures with 1-octanol filled in the lumen of a hollow fiber [6] or supported in the pores of hollow fiber membrane wall [7] were adopted for the measurement of D OW and K OW , whereas negligible depletion solid- * Corresponding author.…”

Simultaneous determination of the lipophilicity and dissociation constants of dialkyl phosphinic acids by negligible depletion hollow fiber membrane-protected liquid-phase microextraction

“…The C O of the analytes increased and then reached a constant with the prolonged extraction time. The time needed to reach a plateau in an increasing order of MEPA < DEPA < MHPA, which more or less mirrors that the rate of exchange between 1-octanol and water decrease with increasing compound hydrophobicity [26]. The 90% and 95% extraction equilibrium time, t 90% and t 95% , estimated according to Eq.…”

“…However, this technique is not applicable for some analytes whose hydrophilicity is fairly strong (log K OW < 0.5) and compounds with identical molar masses [16,25]. Amongst, negligible depletion hollow fiber membranesupported liquid phase microextraction (nd-HF-LPME) has already proved to be a simple, reliable and suitable alternative tool for simultaneous determination of log D and pK a of an ionizable compound [11,26]. With the exception of directly measurement by various experiments, mathematical models are also important tools used in prediction of the K OW and pK a of a compound.…”

The development of a high-throughput measurement method of octanol/water distribution coefficient based on hollow fiber membrane solvent microextraction technique

“…Dialysis tubing has been used to separate two phases and log D is calculated after equilibrium. Hollow fiber membrane solvent microextraction (HFM-SME) for measuring log D is a new direct method developed in our laboratory [25]. The organic phase is injected into a piece of hollow fiber membrane tube, and the aqueous phase was separated from the octanol phase.…”