The effect of the chelator characteristics on adsorption in immobilized metal affinity chromatography

The fact that cryogels have been highly preferred by scientists in chromatographic processes in recent times has made these polymers very popular. These structures are used as an adsorbent in continuous and batch systems. In this study, poly(2- hydroxyethyl methacrylate-glycidyl methacrylate), poly(HEMA-GMA), cryogels were synthesized and then p-aminobenzoic acid and p-aminopyridine compounds were ligated to the structure. Cu(II), Ag(I) and Zn(II) ions were immobilized in the cryogels and these structures were used for adsorption of insulin molecules from aqueous systems. The highest insulin adsorption performance was observed in the cryogel that the p-aminopyridine ligand was bound and the Cu(II) ions were immobilized. Insulin adsorption of cryogels was tested at varying pH, interaction time, initial insulin concentration, temperature and ionic strength. For the characterization of cryogels; Fourier Transform Infrared Spectroscopy (FT-IR), Scanning Electron Microscopy (SEM) analysis, thermal, surface area, elemental and Computerized Microtomography (μCT) analysis methods were performed. The adsorption capacity of the cryogels was estimated as approximately 242 mg insulin/g cryogel. The adsorption process was characterized by Langmuir and Freundlich adsorption models, and Langmuir adsorption model was found to be more suitable. The adsorption kinetics were found to be appropriate for the pseudo-second-order model.