Electrochemical detection of sotalol on a magnetographite-epoxy electrode using magnetite nanoparticles

Sotalol hydrochloride (STHCl) is a cardiovascular agent, specifically an antiarrhythmic and betablocker,that can be used regularly for an extended period. However, it may have side effects, such as weakness and slow heart rate (bradycardia). Currently, techniques such as capillary zone electrophoresis and high-performance liquid chromatography have been widely used for the determination of sotalol hydrochloride, which increases the cost of the analysis. Hence, the aim of this study is to develop an electrochemical sensor, employing magnetographite epoxycomposite (m-GEC) electrode modified with magnetite nanoparticles (MNPs) functionalised with carboxyl for the detection of sotalol as a faster, cheaper, precise and sensitive alternative method. The MNPs have an average size of 7.5 nm and were characterised by transmission electron microscopy. The electrochemical behaviour of STHCl on the m-GEC electrode modified with MNPs, was investigated by cyclic voltammetry and differential pulse voltammetry (DPV). The supporting electrolyte was 0.1 mol l−1 of phosphate buffer solution (pH = 7.0). Two oxidation peaks were observed: at a potential of 720 mV and at 920 mV vs. Ag/AgCl (KCl sat). Differential pulse voltammetry revealed linear calibration curves from 0.5 to 500 × 10−6 mol l⁻¹, with a limit of detection of 0.015 × 10⁻⁶ mol · l⁻¹. Finally, the modified electrode showed good sensitivity, selectivity and stability for the determination of sotalol in real samples. (author)