Selective adsorption of active ingredients liquiritin and isoliquiritin from Glycyrrhiza uralensis Fisch with multi-walled carbon nanotubes(MWNTs) has been studied.Distribution coefficients of liquiritin between ethanol solvent and r-MWNTs or o-MWNTs in 293K is 37.5 and 43.3,while the distribution coefficients of isoliquiritin between ethanol solvent and r-MWNTs or o-MWNTs is 717 and 1080,respectively.It was indicated that the distribution coefficient of isoliquiritin adsorbed by MWNTs was much larger than that of liquiritin,and oxidation treatment of MWNTs could obviously enhance their adsorption ability.The possible reasons that MWNTs can selectively adsorb isoliquiritin other than liquiritin were discussed on the bases of molecular structure of the active ingredients and their interaction with nanotubes.
Multi-wall carbon nanotubes(MWNTs) were irradiated to different doses by Co γ-rays, and were subjected 60 to chemical modification with decylamin. Elemental and TGA analyses of the modified MWNTs indicated that concentration of the functional groups bound to MWNTs increased monotonously with increasing doses, due to the defects created on the MWNTs by the γ-rays. In contrast with the results reported in Ref.1, no saturation of defect concentration was found at 170 kGy in this work.
