Highly Sensitive Amperometric Detection of Hydrogen Peroxide in Saliva Based on N-Doped Graphene Nanoribbons and MnO2 Modified Carbon Paste Electrodes.

Ema Gričar,Boštjan Genorio,Kurt Kalcher,Mitja Kolar

doi:10.3390/s21248301

Ema Gričar, Boštjan Genorio + Show 2 more

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https://doi.org/10.3390/s21248301

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Abstract

Four different graphene-based nanomaterials (htGO, N-htGO, htGONR, and N-htGONR) were synthesized, characterized, and used as a modifier of carbon paste electrode (CPE) in order to produce a reliable, precise, and highly sensitive non-enzymatic amperometric hydrogen peroxide sensor for complex matrices. CPE, with their robustness, reliability, and ease of modification, present a convenient starting point for the development of new sensors. Modification of CPE was optimized by systematically changing the type and concentration of materials in the modifier and studying the prepared electrode surface by cyclic voltammetry. N-htGONR in combination with manganese dioxide (1:1 ratio) proved to be the most appropriate material for detection of hydrogen peroxide in pharmaceutical and saliva matrices. The developed sensor exhibited a wide linear range (1.0–300 µM) and an excellent limit of detection (0.08 µM) and reproducibility, as well as high sensitivity and stability. The sensor was successfully applied to real sample analysis, where the recovery values for a commercially obtained pharmaceutical product were between 94.3% and 98.0%. Saliva samples of a user of the pharmaceutical product were also successfully analyzed.

Highlights

Published: 11 December 2021Hydrogen peroxide (H2O2) is a byproduct in numerous enzymatic processes and in energy conversion devices that utilize the oxygen reduction reaction (ORR)
H2O2 solutions used for measurements were prepared daily by diluting the commercially obtained 30 wt % H2O2 (Sigma-Aldrich, Darmstadt, Germany), which was standardized with KMnO4 titration prior to use
Quasi-1D materials were synthesized by oxidative longitudinal unzipping of MWCNTs, while 2D materials were prepared by oxidative chemical exfoliation of graphite flakes

Summary

Introduction

Hydrogen peroxide (H2O2) is a byproduct in numerous enzymatic processes and in energy conversion devices (fuel cells and Li-air batteries) that utilize the oxygen reduction reaction (ORR). It is widely used as an antimicrobial agent in hygiene and disinfection products, as well as a preservative in food, making it an important analyte in analytical chemistry. Accurate and precise determination of H2O2 using rapid, reliable, and cost-effective approaches is of great importance. Many electrochemical approaches have been developed to determine low concentrations of H2O2 in a high-throughput fashion – in fast, simple, reliable, and inexpensive ways [8,9]

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