Chiral acidic molecularly imprinted polymer for enantio-separation of norepinephrine racemate

Abstract

We are looking into how well a copolymeric material made of poly (maleic acid–co-4-vinylpyridine) cross-linked with divinylbenzene can separate L-norepinephrine (L-NEP) from (±)-NEP. The initial step in this direction was the synthesis and subsequent analysis of L-NEP-maleimide chiral derivative. A 4-vinylpyridine/divinylbenzene combination was copolymerized with the resultant chiral maleimide. After heating the polymer materials in a high-alkaline environment to breakdown the connecting imide bonds, they were acidified in an HCl solution to eliminate the incorporated L-NEP species. Fourier transform infrared spectroscopy (FTIR) and a scanning electron microscope were used to examine the imprinted L-NEP-imprinted materials. The manufactured L-NEP-imprinted materials exhibited selectivity characteristics that were over 11 times greater for L-NEP than D-norepinephrine. The highest capacity observed in Langmuir adsorption studies was 170 mg/g at a pH of 7. After optical separation using a column technique, it was determined that the enantiomeric excess levels of D-norepinephrine and L-NEP in the first feeding and subsequent recovery solutions were 95% and 81%, respectively.