关键词: &beta, -环糊精, 包络物, 电喷雾质谱, 碰撞诱导解离, 相对解离能

Abstract: The positive-and negative-ion electrospray ionization mass spectra of β-cyclodextrin-amino acids complexes in NH₄Ac buffer have been reported in this paper. Compared with positive-ion ESI mass spectra of β-cyclodextrin-amino acids complexes under the same condition, negative-ion mass spectra obtained for inclusion complexes of β-cyclodextrin (CD) with tyrosine, phenylalanine and tryptophan, respectively, were completely dominated by deprotonated complex ions and [CD-H]^- ion which is the only daughter ion in collision-induced dissociation (CID) experiment of deprotonated complexes. The results indicated that the charged position for protonated and deprotonated complexes is different from each other. In addition, two complex ions for the same complex have similarly relative dissociation energies, which are higher than that of [CD+NH₄]⁺, indicating that complexes observed in gas phase are not electrostatic adducts at all but complexes formed by hydrogen bonds.

Key words: β-Cyclodextrin, Inclusion complex, Electrospray ionization mass spectrometry, Collision-induced dissociation, Relative dissociation energy