Preparation of macroporous monoliths based on epoxy-bearing hydrophilic terpolymers and applied for affinity separations

This work reports the synthesis and characterization of poly(N-acryloyl-tris(hydroxymethyl)aminomethane-co-glycidyl methacrylate-co-N,N′-methylenebisacrylamide) [poly(NAT-GMA-BIS)] discs using different porogenic solvents. The macroporous polymer obtained with PEG 6000 as co-porogen showed the best porous properties of the series. End-point immobilization of heparin (Hep, as ligand) was then carried out on the products through reductive amination. Thus, the products were reacted with ethylenediamine (EDA) and hexamethylenediamine (HMDA) in order to introduce amine groups and to analyze the length of the spacer on the immobilization of heparin. Then, the highest value of amine groups [1.280 and 0.919 mmol amine/g dry support for poly(NAT-GMA-BIS)-EDA and poly(NAT-GMA-BIS)-HMDA, respectively] was obtained at 40 °C after 48 h of reaction. Finally, the amount of ligand coupled to discs was not influenced by the two length spacers assayed. The amount of Hep coupled on discs [591.50 and 489.90 μg Hep/g dry polymer for poly(NAT-GMA-BIS)-EDA-Hep and poly(NAT-GMA-BIS)-HMDA-Hep, respectively] was similar to that obtained using macroporous polymer beads reported by other authors. The supports yielded were used to assay the retention of antithrombin III (AT-III). The retention was greater for the EDA-containing product with a larger amount of heparin. These novel heparin-containing macroporous poly(NAT-GMA-BIS) discs could be used as potential affinity chromatography supports.