Rapid method for estimating the octanol–water partition coefficient (log Pow) by microemulsion electrokinetic chromatography

Abstract

Several surfactant systems were evaluated based on their system constants determined by the solvation parameter model for the design of a surrogate chromatographic model for the rapid estimation of octanol–water partition coefficient (log Pow) by microemulsion electrokinetic chromatography. The system constant ratios responsible for the log Pow partition system are (nearly) the same as those for the microemulsion system containing sodium dodecyl sulfate (1.4% w/v), butan-1-ol (8% v/v) and heptane (1.2% v/v). Neutral and basic compounds are analyzed using a fused-silica capillary column with a 50 mM sodium phosphate–sodium borate (3:2) buffer at pH 10. Weakly acid compounds require the use of sulfonated silica capillary column and a 50 mM sodium phosphate buffer at pH 3. For 29 varied neutral and weakly basic compounds the average error between log Pow estimated using MEEKC and literature values was ±0.12 over a log Pow range from 0.3 to 5.8.