| Carbon nanotubes (CNTs) have become one of the most interesting researching stuff in the current material science area because of its unique one-dimensional molecule structure and its special physical and chemical characteristics. Based on the existing studying achievements of our group, the thin layer chromatography (TLC) being assisted with CNTs for chiral separation was studied, the chiral identificaiton ability which was created by differecnt chiral selectors combined with CNTs using physical mixing or chemical bond was discussed.(1) Using beta-cyclodextrin (β-CD), hydroxypropyl-beta-Cyclodextr-in(HP-β-CD) and Methyl-beta-cyclodextrin(Me-β-CD) as chiral selector, the oxidized multi-wall CNTs(Ox-MWCNTs) as stationary phase, the thin layer plate was prepared to separate D,L-propranolol and and R,S-mandelic acid, and solvent system was acetonitrile(CH3CN):tert-butanol(TBA)=1:1. The experiment result showed that three kinds of plates containing three types of cyclodextrin and Ox-MWCNTs can separate D,L-propranolol, and the separation degree can be achieved at4.22/7.14/7.47. The thin layer plates which contained Ox-MWCNTs and HP-β-CD or Me-β-CD can separate R,S-mandelic acid effectively, but the plate containing β-CD and Ox-MWCNTs did not have the same ability.(2) The surface of multi-wall carbon nanotubes was modified by D-tartaric acid. MWCNTs were oxidized by Hydrogen peroxide, then Ox-MWCNTs were mixed with p-Toluenesulfonic acid(p-TSA), Poly(ethylene glycol)(PEG) and D-tartaric acid(D-TA), the solvent condition was N,N-Dimethylformamide(DMF), then the D-TA-MWCNTs were obtained by this esterification reaction. The D-TA-MWCNTs was analysed by Fourier Transform Infrared Spectrometer(FT-IR) and Transmission Electron Microscope(TEM). Using D-TA-MWCNTs as chiral stationary phase in TLC, D,L-propranolol was separated effectively, and the separation degree was7.70. This research showed that the D-TA-MWCNTs expressed a better separation ablility.(3) Beta-cyclodextrin(β-CD) was linked on the CNTs surface. The original multi-wall carbon nanotubes was purified by mixed acid(HNO3:H2SO4=3:1), then the Ox-MWCNTs was functionalized by β-CD under a certain reaction condition. This modified carbon nanotubes was characterized by FT-IR and TEM, and its disparity in water was tested. Using β-CD-MWCNTs as chiral stationary phase in TLC to separate D,L-propranolol, and the separation degree was reached6.60. |
