Boronate affinity monolith via two-step atom transfer radical polymerization for specific capture of cis-diol-containing compounds

Abstract

Boronate affinity (BA) monolith is an important tool for uniquely selective capture of cis-diol-containing compounds. However, most of BA monoliths suffer from limited binding sites. In this work, a high-capacity BA monolith was successfully synthesized via simple two-step atom-transfer radical polymerization method. Fourier transform infrared spectra, scanning electron microscope and Brunauer–Emmett–Teller surface area analyzer were used to characterize the resultant BA monolith. The BA monolith could selective capture of cis-diol-containing small molecular compounds and protein macromolecules with all aqueous mobile phase at pH of 8.5. Frontal analysis was applied to measure the adsorption data, and Scatchard equation was used to calculate the C (Qmax) and dissociation constants (Kd). By using polymer chains to amplify the number of binding sites, the binding capacity of BA monolith had been effectively improved to 303.5 and 118.2 μmol g−1 for catechol and adenosine, respectively. Such binding capacity was the highest among already reported BA monoliths. Interestingly, the binding capacity was mainly depended on the molecular volume (or molecular weight) of cis-diol containing compounds with a significant negative correlation. Besides, via synergistic effect of double binding, the BA chains had enhanced the binding strength of BA monolith toward molecules with two cis-diol groups with Kd value of 10−5 M, which were lower than that of molecules with one cis-diol group by one order of magnitude. The results indicated that the binding capacity and strength depend on not only the property of BA materials but also the nature of cis-diol-containing compounds.