REVERSED-PHASE ION-PAIR CHROMATOGRAPHY WITH AN ADSORBING STATIONARY PHASE AND A HYDROPHOBIC QUATERNARY AMMONIUM ION IN THE MOBILE PHASE .1. RETENTION STUDIES WITH TETRABUTYLAMMONIUM AS CATIONIC COMPONENT

The retention behaviour of some acids (acetylsalicylic acid, naphthalene-2- sulphonic acid, pentobarbital and vinbarbital) and bases (antipyrine, caffeine, codeine, dextropropoxyphene, hydroxyzine and Transergan) have been investigated using μBondapak C18 as stationary phase and a solution of tetrabutylammonium in acetonitrile + aqueous phosphate buffer of pH 3 and 6 (25:75) as the mobile phase. The results indicate that the stationary phase contains sites with different adsorption abilities for hydrophobic ammonium ion paris. Models for the retention have been developed and equilibrium constants for the distrbution of the ion pairs to the hydrophobic stationary phase are presented. © 1979.