ABSTRACT
@#To preparate a novel polysulfone chiral membranes, β-cyclodextrin was functionalized with dodecanoyl chloride, and this modified β-cyclodextrin was then incorporated into polysulfone casting solution to form the dodecanoyl-β-cyclodextrin/polysulfone chiral membrane. Meanwhile, current studies have investigated the effect of adding different amount of dodecanoyl-β-cyclodextrin on the pure water flux, bovine serum albumin(BSA)rejection rate and enantioselectivity of the membranes. The morphology of the dodecanoyl-β-cyclodextrin/polysulfone chiral membrane was characterized by scanning electron microscopy(SEM). With the incorporation of dodecanoyl-β-cyclodextrin, the pore structure of the membrane changed significantly, with more finger-like pore structures appearing in the support layer. So the membrane water flux increased significantly, while the BSA rejection rate decreased. When the addition amount of dodecanoyl-β-cyclodextrin was in the range of 2% to 3. 5%, the enantiomeric excess increased with the addition of dodecanoyl-β-cyclodextrin. A complete separation of racemic tryptophan can be performed using this novel dodecanoyl-β-cyclodextrin/polysulfone chiral membrane-based separation system.
ABSTRACT
A pepsin modified poly (glycidyl methacrylate-ethyleneglycol dimethacrylate)(poly (GMA-EDMA)) capillary monolith (32 cm ×75 μm,22cm effective lenth)was applied in exploring the interaction between nefo-pam enantiomers and bovine serum albumin (BSA),mode of frontal analysis was selected to measure the binding constant,number of binding sites and the location of binding sites of BSA to both nefopam enantiomers.The opti-mal CEC conditions obtained were a running buffer consisted of 15 mmol /L ammonium acetate at pH 5.5,separa-tion voltage 5.0 kV,detection wavelength 215 nm,injection 10 kV ×6 s,solvent of samples consisted of 50 mmol/L ammonium acetate at pH 7.4.The results indicated that the monolith could provide a satisfactory resolution between the two enantiomers plateaus,BSA in the binding system didn′t disturb the separation or determination of nefopam enantiomers in electrochromatography.The frontal analysis demonstrated that BSA has only one binding site with both enantiomers,the binding constants (K)were 443 L/mol and 527 L/mol,respectively,and the dis-placement experiments indicated that binding site of both isomers to BSA molecule was the Sudlow siteⅡ.
ABSTRACT
@#Determination of exact total protein bonding quantity is often a key step in the preparation of protein-immobilized chiral monolith. In this study, we developed and evaluated a bovine serum albumin(BSA)modified monolith based on glycidyl methacrylate(GMA)and ethylene dimethacrylate(EDMA)for chiral separation. The epoxy groups of the polymer were used directly for the covalent bonding of BSA. A Coomassie brilliant blue(CBB)protein assay(Bradford method)was established to determine the protein bonding quantity, and the influence of some key aspects such as ionic strength, pH value and reaction time were studied. The method was validated with respect to linearity, precision, accuracy and robustness. The maximum amount of immobilized BSA was 11. 90 mg/g, obtained using 65 ∶35 cyclohexanol/dodecanol as the porogen. The monolith was successfully applied in the chiral separation of R/S-warfarin and D/L-tryptophan in only 1-20 min. Furthermore, the chromatographic conditions like pH and organic additive of the mobile phase were optimized. The chiral separation performance of this BSA-immobilized monolith is positively correlated to the protein bonding quantity.
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AIM Here the development of a simple, rapid and simultaneous method for the separation of five ephedrine alkaloids obtained with non-aqueous capillary electrophoresis (NACE) were reported. The effects of the electrolyte, non-aqueous solvent on the separation were also discussed. METHODS A running buffer of 50 mmol/L ammonium acetate in methanol was found to be the most suitable for this separation. RESULT The best separation was achieved within 8 minutes. CONCLUSION The separation is not only dependent on differences in the pK value of the alkaloids but also on the intramolecular interaction and solvation. So much improved selectivity could be achieved in nonaqueous medium.
ABSTRACT
Object To develop a rapid method for the determination of ephedrine alkaloids in Ephedra sinica Stapf by nonaqueous capillary electrophoresis (NACE) and evaluate the extracting method by determining the amount of alkaloids Methods The buffer contained 50 mmol/L ammonium acetate in methanol without any additives was used And the detection wavelength was 210 nm Results The best separation result was achieved within 8 min Linearity was obtained in range of 9 8-147 0 ?g/mL pseudoephedrine, 6 8-102 0 ?g/mL for norephedrin, 9 4-141 0 ?g/mL for ephedrine, 4 8-72 0 ?g/mL for norpseudoephdrine, 6 8-102 0 ?g/mL for methylephedrine respectively The recovery range of these five alkaloids was 95 0%-100 4% Conclusion This method is rapid and accurate for the quantitative analysis of ephedrin alkaloids in E sinica
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AIM: To investigate the CE fingerprint of the compound Shengmai Powder(Radix et Rhizoma Ginseng rubra,Radix Ophiopogonis,Fructus Schisandrae chinensis). METHODS: Sequential uniform design was used to optimize the separation conditions. A CE fingerprint for Shengmai Powder was established using buffer comprising 44 mmol/L borate and 34 mmol/L SDS at pH 9. 5,a running voltage of 25 kV,a capillary temperature of 25 ?C and a wavelength of 200 nm. The sample was injected at a pressure of 50 mbar for 100 s. RESULTS: From the fingerprints of eleven batches of sample solutions,twenty main common peaks were determined. four peaks came from Radix et Rhizoma Ginseng,six peaks from Radix Ophiopogonis,thirteen peaks from Fructus Schisandrae chinensis,three peaks shared by Radix et Rhizoma Ginseng and Radix Ophiopogonis,one peak shared by Radix Ophiopogonis and Fructus Schisandrae chinensis and one new constituent. CONCLUSION: The developed method is accurate and reliable,and the fingerprint analysis can be used for the quality assessment and control of compound Shengmai Powder.
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Objective: To investigate the CE fingerprint of Salvia miltiorrhiza . Methods : Separation was performed on a 50?m?50cm uncoated capillary with 20mmol?L -1 borate solution as CE buffer. The run voltage was 15kV and the UV detection was set at 210nm. Results : Fingerprint consisted of 11 common peaks. The validation of methods meet the requirements for SDA's technical regulations. Conclusion : The method was accurate and simple for quality control of Salvia miltiorrhiza.