Search

Here, we report a novel boronate affinity-based surface molecularly imprinted monolith (BA-SMIM), which was fabricated by simple two-step atom-transfer radical polymerization (ATRP) strategy. A boronate affinity-based surface non-imprinted monolith (BA-SNIM) was prepared as control. The synthesis parameters of BA-SMIM were optimized, and the resultant BA-SMIM was characterized in detailed. In both aqueous-rich and organic-rich mobile phases, the BA-SMIM could recognize cis-diol-containing compounds mainly due to the imprinting effect. The chlorogenic acid and rosmarinic acid with two cis-diols could interact synergistically with two imprinting cavities of BA-SMIM, so they retained longer on BA-SMIM than one cis-diol-containing compounds. In addition, the capturing pH reduced from 8.6 on BA-SNIM and to 7.8 on BA-SMIM for one cis-diol-containing compounds, and from 7.4 on BA-SNIM and to 7.0 on BA-SMIM for two cis-diol-containing compounds, respectively. The reducing of capturing pH value on BA-SMIM may be attributed to the nanoconfinement effect of imprinting cavity. [ABSTRACT FROM AUTHOR]

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]

In this study, a new molecularly imprinted polymer chiral stationary phase (MIP-CSP) was prepared utilizing molecular crowding agent for improvement the selective separation ability. S-amlodipine ( S-AML), methacrylic acid (MAA), ethylene glycol dimethacrylate (EDMA), and polymethyl methacrylate (PMMA) were selected as template, functional monomer, cross-linker, and molecular crowding agent, respectively. The composition of formulas for MIP-CSP was optimized, and the permeability and structural feature of resultant MIP-CSP were characterized. The effect of mobile-phase composition, including ionic strength, pH, and organic modifier content, was investigated for achieving the selective separation of rac-amlodipine (rac-AML) on MIP-CSP. The baseline separation of rac-AML was achieved with resolution of 1.58, whereas no selective separation was observed on the imprinted monolith without molecular crowding agent. The perturbation chromatography method was successfully applied to evaluate the recognition mechanism of templates on MIP-CSP. The retention time of S-AML detected in typical analytical conditions was obviously greater than the time of negative peak derived from perturbation, which indicated the retention of template may be due to the imprinted cavities on MIP-CSP. Additionally, the result of Van't Hoff analysis indicated that the chiral separation of rac-AML on MIP-CSP was an entropy-driven process, which supported the molecular imprinting theory. These results reveal that molecular crowding is a potential strategy for preparation of MIP-CSP with excellent selective separation ability. [ABSTRACT FROM AUTHOR]