Enantiomer separation of propranolol and tryptophan using bovine serum albumin functionalized silica nanoparticles as adsorbents

The immobilization of popular chiral selectors on the surface of nanomaterials to prepare new chiral adsorbents for preparative chiral separation is a research hotspot in separation science nowadays. In this study, bovine serum albumin (BSA) modified silica nanoparticles were prepared by using polydopamine (PDA) as a versatile multifunctional secondary reaction platform. The preparation method was facile, cost-effective and environmentally friendly. The new chiral adsorbents were then investigated for the separation of representative chiral drug enantiomers. For propranolol and tryptophan, the multi-step adsorption enhanced the chiral performance to a great degree. On increasing the starting percent enantiomeric excess (%, e.e.) of the enantiomeric mixtures, the %, e.e. value of the resulting solution increased to almost 100% under the same operating conditions. For simplicity and rapidness, the results of adsorption were measured by capillary electrophoresis (CE) using carboxymethyl-beta-cyclodextrin (CM-beta-CD) or alpha-cyclodextrin (alpha-CD) as additives into the background electrolyte solution. The experimental results also showed that the thus-prepared nanomaterials could be readily recycled at least three times, demonstrating their great stability and possibility in practical use.