An electrochemical diclofenac sensor based on an electrode modified with nitrogen-doped biomass-derived carbon and molybdenum trioxide nanoparticles.

Diclofenac (DCF) is a widely used non-steroidal anti-inflammatory drug (NSAID). However, its extensive use has raised health concerns, as overdoses can lead to serious adverse effects. In this research, we developed a novel and portable electrochemical sensor for DCF, which is capable of providing real-time analysis. To promote environmental sustainability, carbon derived from biomass was utilized. Cow dung (CD), a globally abundant and renewable biomass, was selected as the carbon precursor due to its excellent characteristics, including high porosity and large surface area, which are highly beneficial for electrode modification. To enhance electrochemical performance, CD was doped with nitrogen (CD-N) and functionalized with molybdenum trioxide nanoparticles (MoO3NPs). This composite structure significantly improves the electrochemical properties by providing enhanced stability, increased active sites, a larger electroactive surface area, and superior electron mobility, making it a highly effective material for DCF detection. The modified electrode showed an increased active surface area and an improvement in electron transfer performance for DCF oxidation. Under optimal conditions, the electrochemical oxidation of DCF was excellent with a linear range of 0.25-50.00 μmol L-1. The limit of detection was 0.08 μmol L-1. The developed sensor was successfully applied to determine DCF in artificial urine samples, and the results were in accordance with those of spectrophotometric analysis.