Electrochemical detection of regorafenib using a graphite sheet electrode modified with nitrogen-doped reduced graphene oxide nanocomposite

In this work, a modified graphite sheet electrode with large active surface area, porosity and high conductivity was fabricated to detect and measure RGF at very low concentrations in the nanomolar range. [Display omitted] •A novel and sensitive electrochemical sensor for regorafenib drug fabricated based on a monolith reduced graphene oxide nanocomposite modified graphite sheet electrode (M-RGO/GSE).•The M-RGO/GSE shows excellent electrocatalytic activity towards the oxidation of regorafenib.•The sensor exhibits two linear response ranges from 31 nM to 600 nM and 600 nM to 920 nM and a low detection limit of 1.7 nM for regorafenib.•The sensor also demonstrates good selectivity, reproducibility, stability, and recovery in the presence of potential interfering substances and in real samples.•The sensor provides a simple, fast, and cost-effective method for the electrochemical detection of regorafenib in clinical applications. Regorafenib (RGF) is a multi-kinase inhibitor drug used for treating various cancers, posing challenges for detection in biological samples due to low solubility and stability. This paper presents a novel electrochemical sensor based on a monolith reduced graphene oxide (M-RGO) nanocomposite modified graphite sheet electrode. M-RGO was synthesized via a hydrothermal method and characterized extensively. The electrochemical performance was assessed using cyclic voltammetry and differential pulse voltammetry. The sensor demonstrated exceptional electrocatalytic activity for RGF oxidation, featuring two linear response ranges (31 nM to 600 nM and 600 nM to 920 nM) with a detection limit of 1.7 nM. The sensor exhibited good selectivity, stability, and reproducibility. Successful application in determining RGF in human serum and urine samples demonstrated the potential of M-RGO nanocomposite as a promising material for the development of electrochemical sensors for pharmaceutical analysis.