Search

The molecularly imprinted magnetic stir bar coatings were created based on graft-functional Fe 3 O 4 nanoparticles with magnetic field-induced self-assembly. The magnetic complex including clonazepam as template, the graft-functional Fe 3 O 4 nanoparticles and methacrylic acid as monomers was pre-assembled through π–π interaction and hydrogen bonding, then was directionally adsorbed on the surface of magnetic stir bar under the magnetic induction. The molecularly imprinted coating with well-ordered structure was generated by one-step copolymerization based on the cross linking of ethylene glycol dimethacrylate. The molecularly imprinted coating with multiple recognition sites could be manufactured and applied in polar solvents, and showed superior selectivity and fast binding kinetics for benzodiazepines. The analytes in herbal health foods, treated by stir bar sorptive extraction, were determined by HPLC-UV. Good linearity was observed in the range of 0.01–2 μg mL −1 . The content of clonazepam in the herbal health foods was found to be 44 ng g −1 , and the average recoveries were 89.8–103.3% with a relative standard deviation (RSD) <6.5%, demonstrating the successful application in real sample analysis. [ABSTRACT FROM AUTHOR]

Several research have reported that silver ions (Ag + ) could enhance the photoluminescence of some kinds of gold nanoclusters (AuNCs), and redox reaction involved mechanisms were recognized as the main reason to cause such phenomenon. However, in this work, we found that Ag + could enhance the luminescence of aggregation-induced emission gold nanoclusters (AIE-AuNCs) without valence state change. Upon addition of Ag + , the luminescence of AIE-AuNCs enhanced instantly by 7.2 times with a red-shift of emission peak and a complete restoration of luminescence features was observed when Ag + was removed. A cost-effective, rapid-response, highly sensitive and selective method to detect trace amount of Ag + has thereby been established using AIE-AuNCs as a nanosensor. This analytical method exhibited a linear range of 0.5 nM–20 μM with a limit of detection of 0.2 nM and it showed great promise for Ag + monitoring in environmental water. [ABSTRACT FROM AUTHOR]

A molecularly imprinted stir bar was constructed based on Fe 3 O 4 @Polyaniline nanoparticles with magnetic field-induced self-assembly process. The monomer, methacrylic acid, was pre-assembled into the pre-polymers with vanillin as template by the formation of hydrogen bonds. After that, the magnetic complexes were generated by the hydrogen bonding, the hydrophobic and π–π interaction between the pre-polymers and Fe 3 O 4 @Polyaniline. The complexes were adsorbed on the surface of magnetic stir bar under the magnetic induction, and the coating of vanillin-molecularly imprinted polymers was generated by the one-step copolymerization basing on the cross linking of ethylene glycol dimethacrylate. The molecular imprinting stir bar showed superior selectivity and fast binding kinetics for vanillin, and was used for the enrichment of vanilla-flavor enhancers (vanillin, ethyl maltol and methyl vanillin) in infant milk powders. The results measured by HPLC-UV exhibited good linear ranges of 0.01–100, 0.02–100 and 0.03–100 μg mL −1 with the limit of detection of 2.5–10.0 ng mL −1 , and the recoveries were 94.7–98.9%, 82.1–96.7% and 84.5–93.2% with RSD < 7.2% for the three enhancers, respectively. [ABSTRACT FROM AUTHOR]