Characterization of sulfobutyl ether-beta-cyclodextrins mixtures by anion-exchange chromatography using evaporative...

An analytical method based on anion-exchange chromatography (AEC) using volatile eluent ion and evaporative light scattering detection was developed for the analysis of mixtures of sulfobutyl-ether-beta-cyclodextrins (SBE-beta-CDs). A systematic investigation of the retention mechanism of pure SBE-beta-CD standards has been studied on a silica quaternary ammonium exchanger (Vydac 302 IC column). The influence of the nature and concentration of volatile anions (acetate, formate, trifluoroacetate), the addition of the organic modifier in the mobile phase as well the nature of the stationary phase have been evaluated under isocratic elution conditions. Satisfactory analysis of two commercial and two home-made SBE-beta-CD samples was achieved on the Vydac 302 IC column by using ammonium acetate as ion eluent in water-acetonitrile (70:30) under a salt concentration gradient mode. This method provides for SBE-beta-CD samples, an efficient and characteristic liquid chromatography fingerprint which depicts the mixture complexity and determines an average degree of substitution (DS) for each sample.