A COMPARISON OF WATER-SODIUM DODECYL-SULFATE PHASE-TRANSFER LINEAR SOLVATION ENERGY RELATIONSHIPS AND DATABASES

Four linear solvation energy relationship (LSER) studies of solute par titioning in aqueous sodium dodecyl sulfate micellar solutions are com pared. Two of the LSERs are based on compilations of literature data o btained from a variety of measurement techniques and under differing e xperimental conditions. A third study used micellar electrokinetic cap illary chromatography (MEKC) to obtain partition coefficients, whereas our approach is based solely on a head space gas chromatographic (HSG C) method. Despite significant differences in the sizes of the solute sets, the four LSERs yield essentially equivalent chemical conclusions regarding the fundamental interactions controlling the partition proc ess. In comparison to MEKC, HSGC does not require the presence of salt or buffers, although it can be done with such additives, including co surfactants. Additionally, the HSGC method, unlike the MLC method, doe s not involve assumptions concerning the behavior of any stationary ph ase. There are few restrictions on the HSGC method since one can use i t to study species which are present in very low concentrations and wh ich do not have chromophore. Finally, based on Kamlet's recommendation that three to four solutes are needed to properly define each LSER co efficient, we suggest a set of about 20 preferred solutes to use for f uture LSER studies of micellar systems. (C) 1997 Academic Press.