Relationship between hydrophobic properties of amphoteric sulfonamides and their retention in micellar reversed phase liquid chromatography

The partition coefficients of 10 selected sulfonamides in the system octanol-water (P-ow) and their retention coefficients (k) in RP HPLC with anion micellar mobile phase were determined. The mechanism of retention of the sulphonamides studied was analysed depending on the concentration of sodium dodecylsulphate in the mobile phase and pH of the latter. Relationship between the partition coefficients and retention coefficients was established. It was shown that apart from P-ow, a measure of the hydrophobic character of such amphoteric' compounds as the sulfonamides studied, could be the values of the retention coefficient determined at pH of the isoelectric point.