Separation Of Enantiomers And Analogues On Chiral Chromatography And Molecularly Imprinted Membrane

Since D,L-tryptophan were retained by bovine serum albumin (BSA) and had a well-characterized change in retention under various chromatographic conditions, BSA and D,L-tryptophan were used as chiral selector and analytes, respectively. By comparing with BSA chiral stationary phases (BSA-CSPs) prepared by several protein immobilizing methods, the BSA-CSP prepared by 1,1-carbonyldiimidazole (CDI) method was determined to be the best. The binding of D,L-tryptophan on this BSA-CSP was examined by using the frontal analysis (FA) method. The data were obtained to determine the amount of binding sites on BSA-CSP and the association equilibrium constants for D,L-tryptophan at these sites under a wide range of chromatographic conditions. And the thermodynamic parameters for D,L-tryptophan on this BSA-CSP were determined from the plots of lnk'versus 1/T.Postulating totally enantiomeric separation, in order to decrease needed time and mobile phase, common method to prepare BSA-CSP with CDI was improved. A film of hydrophilic chitosan was covalently coupled on the aminopropyl silica before immobilization of BSA. It can weaken hydrophobic interaction between enantiomers and albumin and decrease the retention time of the enantiomers. And the effects of various conditions of mobile phase and the sample on the retetion factor k'and separation factorαof D,L-tryptophan were investigated.Chromatographic band profiles were simulated with Equilibrium Diffusion model and competitive BiLangmuir isotherm. The variations of the parameters in the chromatographic model at varied preparative and chromatographic conditions were used to explain the binding mechanism between the analytes and the BSA-CSP. These parameters were determined by inverse method and a good fitting between the calculated band profiles and experimental chromatograms was obtained by adjusting the values of these parameters.Molecularly imprinted polymers (MIP) were synthesis using acrylamide (AA) as functional monomer instead of methacrylic acid (MAA) in acetonitrile. The recognition of MIP using AA as functional monomer was stronger than MIP using MAA as functional monomer. MIP using AA as functional monomer was examined by linear gradient elution and in aqueous media.A very thin of MIP that can specifically and selectively absorb the basic template(adenine) was grafted on the surface of the polyvinylidene fluoride membrane by photo-grafting copolymerization. Because the MIP is grafted on the surface of the matrix membrane without blocking the membrane pores, the resultant molecular imprinted polymer membrane have high flux as microfiltration membrane (0.26 mol·m-2·h-1 of template and flux for distilled water was 3.6 ml·mim-1cm-2 at 0.8 MPa).