Characterization of modified cyclodextrins applied in capillary electrophoresis and high-performance liquid chromatography as chiral selectors by matrix-assisted laser desorption ionization curved field reflectron mass spectrometry

The use of ultraviolet (UV) matrix-assisted laser desorption ionization mass spectrometry combined with a curved field reflectron analyzer is demonstrated for the characterisation of samples of beta-cyclodextrin (1) and five modified cyclodextrins (2-6) often applied in chiral separation techniques. Sodiated and sometimes potassium-adduct molecular ions are observed in the reflectron mode for all compounds studied with a mass accuracy between -0.02% and +0.09%. Characteristic molecular ion patterns for the heterogeneous samples 3-6 [methylated, (2-hydroxy)-propylated and carboxymethylated beta-cyclodextrins] appear in the positive-ion spectra corresponding to the various degrees of substitution. Two different matrices, alpha-cyano-4-hydroxycinnamic acid with the thin-layer deposition technique and 2,5-dihydroxybenzoic acid with the volume preparation technique have been used. (C) 1997 Elsevier Science B.V.