A novel molecularly imprinted nanobifunctional silica probe on the surface of black phosphorus nanosheets for the determination of trace norfloxacin by its catalytic amplification in RRS

Abstract

A new black phosphorus nanosheets loaded with gold nanoparticles (BPNs-Au) by in-situ reduction procedure were prepared. Using BPNs-Au as the substrate, norfloxacin (NOR) as the template molecule, and 3-aminopropyltriethoxysilane (APTES) as the functional monomer, a surface molecularly imprinted nanosilica probes (BPNs-Au@MIP) with high catalytic properties were rapidly synthesized by the reversed-phase emulsion procedure, and the probes were also characterized in details. It was found that the BPNs-Au@MIP nanoprobe could specifically recognize NOR and had a strong catalytic effect on the nanogold indication reaction of ethanedioic acid-chloroauric acid. The generated AuNPs exhibit strong resonance Rayleigh scattering (RRS) effect and RRS was used as monitoring technique for the nano indicator reaction. After the addition of NOR, the catalytic sites of the nanoprobe were blocked by it, the catalytic activity was reduced, and the RRS signal was linearly weakened. As a result, we constructed a new RRS analysis platform for highly sensitive and selective determination of 0.0625–0.5 nmol/L NOR, with a detection limit of 0.035 nmol/L NOR. The method has been used for the determination of NOR in real samples, and the relative standard deviations (RSDs) were in the range of 3.54–7.43 %, with the recovery of 89.8–109.7 %.