Silver nanoparticles built-in zinc metal organic framework modified electrode for the selective non-enzymatic determination of H2O2

- GC electrode was modified with AgNPs-Zn-MOF.
- It was used for the sensitive and selective determination of H2O2.
- The AgNPs-Zn-MOF modified electrode exhibited high stability and reproducibility towards H2O2.
- Practical application was demonstrated by determining H2O2 in milk, human urine and blood serum samples.

In this paper, the selective and sensitive determination of hydrogen peroxide (H2O2) at physiological pH using silver nanoparticles-zinc-metal organic framework (AgNPs-Zn-MOF) modified glassy carbon (GC) electrode was described. Initially, the Zn-MOF was synthesized by hydrothermal method and then incorporated with AgNPs capped tannic acid. The AgNPs-Zn-MOF was characterized by fourier transform infrared spectroscopy (FT-IR), X-Ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) transmission electron microscopy (TEM) and energy dispersive X-ray analysis (EDX). The SEM image shows that the AgNPs in Zn-MOF were spherical in shape with an average size of ∼50 nm. Then, the synthesized AgNPs-Zn-MOF was modified on GC electrode by drop casting and the resulting modified electrode was characterized by cyclic voltammetry (CV) and electrical impedance spectroscopy (EIS). The CV of AgNPs-Zn-MOF modified electrode exhibits a sharp anodic peak at +0.20 V corresponding to the oxidation of Ag0 to Ag+ and a subsequent reduction peak at −0.50 V corresponding to Ag+ to Ag0. Further, the electrocatalytic activity of the AgNPs-Zn-MOF modified electrode was examined by studying the reduction of H2O2. It exhibits a sharp reduction peak for H2O2 at −0.67 V with a current of −21 μA whereas no response was observed at GC, GC/Zn-MOF and GC/TA-AgNPs modified electrodes. The current response of H2O2 was increased linearly while increasing its concentration from 1 μM to 5 mM with a correlation coefficient of 0.9915 and a limit of detection was found to be 67 nM (S/N = 3). The practical application of the present method was demonstrated by determining H2O2 in milk, human urine and blood serum samples.

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