One-stage chiral enrichment process by continuous flow electrodialysis with molecularly imprinted membrane

The purification and separation of amino acid enantiomeric compounds, such as dl-phenylalanine (dl-Phe), are attracting increasing attention in the biomedical and pharmaceutical fields. In this study, an enantioselective l-Phe molecularly imprinted membrane (l-Phe-MIM) was prepared via a surface grafting reaction. The membrane performances in the separation and enrichment of dl-Phe were investigated by using a continuous-flow electrodialysis system. The synthesis and electrodialysis parameters were optimized to obtain the maximum separation ratio. The selectivity for dl-Phe can be switched by changing the template from l-Phe to d-Phe. This suggests that the MIM is controlling the selectivity in the continuous flow electrodialysis system. The membrane prepared via a layer-by-layer process gave improved selectivity. The results show that excellent chiral separation and high stability were achieved, with a selectivity (l/d) of 2.95 ± 0.34. The results of this study offer new insights into, and perspectives on, obtaining enhanced chiral compound separation by continuous electrodialysis with a MIM in a single-pass process within ∼ 10 s.