Fabrication and employment of cobalt-doped yttrium iron garnets for the electrochemical analysis of anti-diabetic, metformin in serum of type 2 diabetes mellitus patients

Metformin (MET) is an anti-diabetic drug employed as the first-line therapy for patients of type II diabetes mellitus (T2DM). Overdosage of drugs leads to severe outcomes, and its monitoring in biofluids is vital. The present study develops cobalt-doped yttrium iron garnets and employs them as an electroactive material immobilized on a glassy carbon electrode (GCE) for the sensitive and selective detection of metformin via electroanalytical techniques. The fabrication procedure via the sol–gel method is facile and gives a good yield of nanoparticles. They are characterized by FTIR, UV, SEM, EDX, and XRD. Pristine yttrium iron garnet particles are also synthesized for comparison, where the electrochemical behaviors of varying electrodes are analyzed via cyclic voltammetry (CV). The activity of metformin at varying concentrations and pH is investigated via differential pulse voltammetry (DPV), and the sensor generates excellent results for metformin detection. Under optimum conditions and at a working potential of 0.85 V (vs. Ag/AgCl/3.0 M KCl), the linear range and limit of detection (LOD) obtained through the calibration curve are estimated as 0–60 μM and 0.04 μM, respectively. The fabricated sensor is selective for metformin and depicts a blind response toward interfering species. The optimized system is applied to directly measure MET in buffers and serum samples of T2DM patients.