Rapid method for estimating the octanol-water partition coefficient (log P-ow) by microemulsion electrokinetic chromatography

Several surfactant systems were evaluated based on their system constants d etermined by the solvation parameter model for the design of a surrogate ch romatographic model for the rapid estimation of octanol-water partition coe fficient (log P-ow) by microemulsion electrokinetic chromatography. The sys tem constant ratios responsible for the log P-ow partition system are (near ly) the same as those for the microemulsion system containing sodium dodecy l sulfate (1.4% w/v), butan-1-ol (8% v/v) and heptane (1.2% v/v). Neutral a nd basic compounds are analyzed using a fused-silica capillary column with a 50 mM sodium phosphate-sodium berate (3:2) buffer at pH 10. Weakly acid c ompounds 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 com pounds the average error between log P-ow estimated using MEEKC and literat ure values was +/-0.12 over a log P-ow range from 0.3 to 5.8. (C) 2000 Else vier Science B.V. All rights reserved.