Selective Detection of Trace Metronidazole by Using a Magnetic Molecularly Imprinted Polymer‐based Fluorescent Probe

Abstract

A magnetic molecularly imprinted polymer-based fluorescent (MIP-FL) probe has been synthesized by embedding glutathione-stabilized gold nanoclusters (GSH-AuNCs) and Fe 3 O 4 nanoparticles (Fe 3 O 4 NPs) into silica composites. The Fe 3 O 4 NPs/AuNCs@MIPs are characterized by scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectroscopy, and UV-Vis absorption spectroscopy. The results show that the spherical Fe 3 O 4 NPs/AuNCs@MIPs contain a core-shell structure with GSH-AuNCs anchored on the surface of silica-protected Fe 3 O 4 NPs. As a fluorescence probe (excitation: 360 nm, emission: 615 nm), Fe 3 O 4 NPs/AuNCs@MIPs can selectively detect metronidazole (MNZ) among other nitroimidazoles (ronidazole, ornidazole, and tinidazole). During the detection, the fluorescence intensity of the MIP-FL probe drops gradually with increasing MNZ concentration. The sensitive linear range of the fluorescence probe is from 0 to 5 μM, and the limit of detection is 4.2 nM. After the recognition sites interact with the template, the occurrence of charge transfer from the GSH-AuNCs to MNZ results in fluorescence quenching. Finally, a real sample test has been performed in spiked milk. Satisfactory recoveries spanning from 96% to 102% indicate that Fe 3 O 4 NPs/AuNCs@MIPs enable highly sensitive detection of MNZ based on fluorescence signal output, while the MIPs also have enrichment potential for the target from complex samples due to the magnetic properties.

Isothermal Modelling of the Adsorption of Chromium onto Calcium Alginate Nanoparticles

“…The calculated Langmuir parameters qmL value of 79.174 mg/g (95% confidence interval from 50.702 to 107.646) and bL value of 0.332 L/mg (95% confidence interval from 0.294 to 0.371) is not much different from the linearized published work for the qmL value of 145 mg/g but lower than the bL value of 0.34 L/mg [23]. A broad range of sorbents, including nanomaterials with various forms of coating and chemical synthesis method as well as other approaches, can be used to remove trace elements from freshwater [46][47][48][49][50][51]. Nanomaterials, which are defined as materials and structures with at least from 1-100 nm offer different mechanical, optical, magnetic, and chemical properties with respect to particles and macroscopic surfaces of similar consistency.…”

A magnetic molecular imprinting‐based fluorescence probe for sensitive and selective detection of 2,4‐D herbicide

“…Fe 3 O 4 NPs@SiO 2 were synthesized using our developed method [26]. In addition, the APTES–NBD conjugates were synthesized according to a previous report [27].…”

Aggregates‐based fluorescence sensing technology for food hazard detection: Principles, improvement strategies, and applications

“…(a) Aptamer–magnetic nanoparticles (MNPs) combined with IgG–TPE–OH@ bovine serum albumin (BSA) NPs for Listeria monocytogenes detection; (b) a trisnaphthalimide derivative‐based supramolecular sensor for detecting picric acid (PA) and CN − (Lin et al., 2019); (c) tetraphenylpyrazine‐based aggregation‐induced emission luminogens (AIEgens) combined with molecularly imprinted polymer (MIP) for rhodamine 6G detection (Li, He, et al., 2019); (d) a spherical MIP for metronidazole detection (Tan et al., 2019); (e) an assay of metformin (MET), based on the host–guest molecular recognition of cucurbit[6]uril (CB[6])‐AgNPs (Song et al., 2019); (f) multiple anchored fluorene dimers as an aggregate base for dinitrate detection (Jia, Xu, et al., 2019); (g) a coumarin and TPE contained supramolecular network fluorescence sensor for cyclen, Et 3 N, and Cl − detection (Xu, Chen, et al., 2018). …”

“…Tan et al. (2019) designed a spherical MIP for metronidazole detection in an aqueous solution, in which GSH–AuNCs, as the signal part due to their AIE properties, were anchored on the surface of silica‐protected Fe 3 O 4 NPs (Figure 7d). After the enrichment of metronidazole under an external magnetic field by this MIP, the occurrence of charge transfer from the GSH–AuNCs to analytes resulted in fluorescence quenching.…”