RAPID-DETERMINATION OF LOGARITHMIC PARTITION-COEFFICIENTS BETWEEN N-OCTANOL AND WATER USING MICELLAR ELECTROKINETIC CAPILLARY CHROMATOGRAPHY

Micellar electrokinetic capillary chromatography (MECC) was evaluated as a rapid screening tool for the determination of logarithmic partition coefficients between n-octanol-water (log P-OW). The technique is performed by electrochromatographing a mixture of standards of known log P-OW. The logarithmic capacity factor of each standard was plotted against its log P-OW to form a linear calibration curve for a given set of chromatographic conditions. The log P-OW of an unknown is calculated by using its chromatographically determined capacity factor and extracting the log P-OW value from the calibration curve. The method was evaluated with a set of model compounds with known log P-OW. The accuracy of the method was examined and found to be within the limits required for screening purposes. The correlation of log P-OW values determined using HPLC and MECC for some novel compounds was examined. This technique allows the screening of log P-OW at a rate of four samples per hour with minimal sample requirements (< mu g) and with extremely small solvent waste generated.