Preparation Of Citric Acid-β-cyclodextrin/SiO₂-TiO₂ Hybrid Open Tubular Column And Its Application To Capillary Electrochromatography-Mass Spectrometry

A new type of open tubular column was prepared with organic-inorganic hybrid materials including derivatived cyclodextrin as stationary phase, and it was applied in CEC-MS to separate chiral drug mixtures. That is, a CA-β-CD/SiO2-TiO2 open tubular capillary electrochromatography column was prepared by sol-gel method and solvent hot method with silicate(TEOS) and titanate(TBOT) used as inorganic precursors and CA-β-cyclodextrin as organic groups. The effects of the mass ratio of organic and inorganic phase, the mass ratio of water and the inorganic phase, the volume of hydrochloric acid and the reaction temperature on sol state have been studied. The influences of solvothermal temperature and time on column permeability and bonding conditions have been investigated. The microstructure, thermostability of hybrid materials, and the morphology of stationary phase in open tubular column were characterized by infrared spectroscopy(IR), thermogravimetry(TG) and scanning electron microscopy(SEM), respectively. These results show that the stationary phase with uniform thickness in capillary is obtained by chemical bonding. The column efficiency and reproducibility of the hybrid open column were evaluated with thiourea as a neutral marker. RSD of the rentention time is 2.16%, the average column efficiency obtained is 17635 plates/m, and RSD of column efficiency is 2.68%. These results show that the hybrid open tubular column has good reproducibility. The chiral separation performance of the hybrid open column was evaluated with the enantiomeric mixtures of tyrosine and tryptophanthe, and baseline separation of the four components from two kinds of amino acids was achieved, which show that the hybrid open tubular column has very good chiral separation ability. Finally, under the optimal separation conditions of CEC and detection conditions of MS, the column was applied to CEC-MS to separate the chiral drug mixtures of isoprenaline hydrochloride and clorprenaline hydrochloride. Baseline separation of the four components of two chiral drugs was also achieved, and their resolutions were 1.62, 4.68 and 1.53, respectively.