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

In this paper, the selective and sensitive determination of hydrogen peroxide (H 2 O 2 ) 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 Ag 0 to Ag + and a subsequent reduction peak at −0.50 V corresponding to Ag + to Ag 0 . Further, the electrocatalytic activity of the AgNPs-Zn-MOF modified electrode was examined by studying the reduction of H 2 O 2 . It exhibits a sharp reduction peak for H 2 O 2 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 H 2 O 2 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 H 2 O 2 in milk, human urine and blood serum samples. [ABSTRACT FROM AUTHOR]