Fabrication of imidazolium-functionalized magnetic composite microspheres for selective recognition and separation of heme proteinsElectronic supplementary information (ESI) available. See DOI: 10.1039/c7nj00109f

In this work, a facile route was presented to fabricate magnetic composite microspheres composed of a high-magnetic-response magnetic microsphere Fe 3 O 4 core and an imidazolium-modified poly 4-vinylbenzylchloride (pVBC) shell via distillation-precipitation polymerization. The applicability of the as-synthesized Fe 3 O 4 @SiO 2 @pVBC@IL magnetic composite microspheres (MMPs) was investigated in the selective recognition and separation of heme proteins mainly based on the covalent coordination between the ferrous ion in the heme group of the heme proteins and the imidazolium cation. The experimental results showed that Fe 3 O 4 @SiO 2 @pVBC@IL MMPs exhibited high hemoglobin binding capacity (6321 mg g −1 ), which was due to the pure pVBC@IL interface and high imidazolium ion loading amount, and high efficiency and excellent selectivity in the isolation of hemoglobin from a protein mixture and human blood samples. These good results demonstrate that the prepared MMPs could be applied in the removal of high abundant protein (heme proteins) from samples before proteomic analysis. Imidazolium-functionalized magnetic composite microspheres were successfully synthesized, which exhibited high hemoglobin binding capacity (6321 mg g −1 ) and excellent selectivity.