Molecularly imprinted polymer functionalized nanoporous Au-Ag alloy microrod: Novel supportless electrochemical platform for ultrasensitive and selective sensing of metronidazole

• Novel electrochemical sensor was fabricated facilely via in situ dealloying and MIT.
• The MIP-wrapped microrod with nanoporous surface can solely act as an electrode.
• Ultralow detection limit for sensing MNZ is down to 10−2 ppt via cyclic voltammetry.
• It owns wide detection range, good selectivity and stability in spiked biosamples.

We describe here an ultrasensitive electrochemical detection of metronidazole (MNZ) by using a freestanding Au-Ag alloy microrod (AMR) as working electrode. Nanoporous Au-Ag AMR (NPAMR) was facilely prepared by dealloying of smooth AMR and further modified with electropolymerized molecularly imprinted polymer (MIP), which affords simultaneous identification and quantification of the target molecules by cyclic voltammetry (CV) with Fe(CN)63−/4− as probe to indicate the current intensity. The MIP-decorated NPAMR showed a remarkably low detection limit of 2.7 × 10−14 M (S/N = 3) and a wide determination range from 8.0 × 10−14 to 1.0 × 10−6 M for MNZ. The developed sensor has been successfully applied in detection of MNZ in real samples (fish tissues and drug tablet), and admirable specificity and anti-interference capability were achieved. This protocol offers great promise for cost-effective and precisely quantitative analysis of trace biological and chemical substances without assistance of any extra working electrode.

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