Characterization of sulfobutyl ether-beta-cyclodextrins mixtures by anion-exchange chromatography using evaporative light scattering detection

An analytical method based on anion-exchange chromatography (AEC) using vol atile eluent ion and evaporative light scattering detection was developed f or the analysis of mixtures of sulfobutyl-ether-beta -cyclodextrins (SBE-be ta -CDs). A systematic investigation of the retention mechanism of pure SBE -beta -CD standards has been studied on a silica quaternary ammonium exchan ger (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 p hase have been evaluated under isocratic elution conditions. Satisfactory a nalysis of two commercial and two home-made SBE-beta -CD samples was achiev ed on the Vydac 302 IC column by using ammonium acetate as ion eluent in wa ter-acetonitrile (70:30) under a salt concentration gradient mode. This met hod provides for SBE-beta -CD samples, an efficient and characteristic liqu id chromatography fingerprint which depicts the mixture complexity and dete rmines an average degree of substitution (DS) for each sample. (C) 2000 Els evier Science BN. All rights reserved.