Search

In this work, we reported an effective method for the synthesis of a multirecognition magnetic molecularly imprinted polymer (MMIP) with atom transfer radical polymerization (ATRP), using 2,4-diamino-6-methyl-1,3,5-triazine as pseudo-template. The resulting MMIP was characterized in detail by Fourier transform-infrared (FT-IR) spectra, scanning electron microscopy (SEM), thermogravimetic analysis (TGA), and vibrating sample magnetometry (VSM). These results indicated the successful synthesis of MMIP with sufficient thermal stability and magnetic properties. The adsorption experiments were carried out to evaluate the specific selectivity of MMIP related to the spatial structure of target molecules. The MMIP exhibited multirecognition ability and excellent binding capability for melamine (MEL), cyromazine (CYR), triamterene (TAT), diaveridine (DVD), and trimethoprim (TME), and the apparent maximum number of binding sites ( Q ) was 77.5, 75.2, 72.5, 69.9, and 70.4 μmol g, respectively. The multirecognition MMIP not only possessed adequate magnetic responsiveness for fast separation but also avoided the risk of template leakage on trace component analysis. Therefore, it was suitable for serving as a magnetic solid-phase extraction (MSPE) adsorbent. MSPE coupled with high-performance liquid chromatography analysis was applied to enrich and separate five target molecules from three samples. Recoveries for all target molecules ranged from 81.6 to 91.5% with relative standard deviations of no more than 4.1% ( n = 3). [ABSTRACT FROM AUTHOR]

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 (Q max ) and dissociation constants ( K d ). 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 K d 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. [ABSTRACT FROM AUTHOR]