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

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 mu M) and an excellent limit of detection (0.08 mu M) 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.

Automated summary

Four different graphene-based nanomaterials were synthesized, characterized, and utilized as modifiers of carbon paste electrodes to develop a non-enzymatic amperometric hydrogen peroxide sensor for complex matrices. The optimized sensor exhibited a wide linear range, excellent detection limit, and high stability, making it suitable for real sample analysis in pharmaceutical and saliva matrices. The recovery values for commercial pharmaceutical products and saliva samples demonstrated the accuracy and reliability of the sensor in practical applications.