Analysis of partially methylated cyclodextrins by subcritical fluid and liquid chromatography

Liquid and subcritical chromatographic analyses using evaporative light scattering detection were used to investigate the composition of various commercial dimethylated beta-cyclodextrins (beta-CD). The chromatographic fingerprints better depict the complexity of each mixture than the degree of substitution. The elution order is reversed when subcritical fluid chromatography is used instead of LC on apolar stationary phases (TMS and phenyl columns). Concerning the RPLC analysis of methylated beta-CD, a phenyl-bonded silica column offers selectivities that are different from those obtained using a classical C-18-bonded silica column. With regard to the more complex mixtures, SubFC allows one to obtain richer methylated beta-CD fingerprints than does LC.