Design of chiral acidic molecularly imprinted polymer for the enantioselective separation of (±)-DOPA

Background

The study focuses on developing a stable enantioselective matrix for the efficient chiral identification and enantioresolution of l-DOPA and (±)-DOPA. The matrix is derived from a copolymeric material made from poly[(vinylsulfonic acid)-co-(4-vinylpyridine)] crosslinked with divinylbenzene.

Results

l-DOPA-vinylsulfonamide was synthesized and characterized. This chiral sulfonamide was copolymerized with 4-vinylpyridine in the presence of a divinylbenzene crosslinker, using azobisisobutyronitrile as a thermal initiator. Post-polymerization, the polymeric particles were treated with NaOH and subsequently washed with acid to remove the integrated l-DOPA species. Scanning electron microscopy and Fourier transform infrared spectroscopy confirmed the imprinted l-DOPA-IP particles. The manufactured l-DOPA-IP demonstrated a tenfold greater affinity for l-DOPA compared to d-DOPA. Langmuir adsorption experiments at pH 6 showed a maximum capacity of 162 mg g⁻¹. Enantiomeric excess values for l- and d-DOPA, determined through optical separation using a column approach, were 94% and 82%, respectively, in the loading and recovery solutions.

Conclusion

The developed copolymeric material effectively served as an enantioselective matrix, exhibiting high selectivity and capacity for l-DOPA. The process demonstrated efficient chiral identification and separation, achieving significant enantiomeric excess values for both l- and d-DOPA. © 2024 Society of Chemical Industry (SCI).