Preparation of a boronate affinity material with ultrahigh binding capacity for cis-diols by grafting polymer brush from polydopamine-coated magnetized graphene oxide.

Poly(3-acrylamidophenylboronic acid) (PAAPBA) was grafted onto polydopamine-coated magnetic graphene oxide via surface-initiated atom transfer radical polymerization to obtain a new kind of boronate affinity material (BAM). The BAM possesses good water dispersity and adsorption capacities as high as 154, 357, 588 and 1111 μmol·g for adenosine, salbutamol, dopamine and catechol, respectively. For the molecules without nitrogen atoms, the BAM can selectively capture the cis-diols under the interference of non-cis-diols. For molecules containing nitrogen, the non-cis-diols are also retained, but much less than the cis-diols. The selectivity can be improved by adding salts to facilitate complexation and to suppress the electrostatic interaction between cis-diols and the boronic acid ligand. The BAM was successfully employed to the enrichment of catecholamines from real urine samples. Results indicate that it is a promising material for the pretreatment of real samples. Graphical abstract Schematic of the preparation of an ultrahigh capacity boronate affinity material by grafting polymer brush from polydopamine coated magnetic graphene oxide. The material has good selectivity to cis-diol-containing molecules and can be applied to enrich catecholamines in urine samples.