Hexammine cobalt(iii) coordination complex grafted reduced graphene oxide composite for sensitive and selective electrochemical determination of morin in fruit samples

Abstract

In this report, we have successfully prepared the hexammine cobalt(III) coordination complex [Co(NH₃)₆]³⁺ grafted onto a reduced graphene oxide (RGO) composite modified glassy carbon electrode (GCE) for the electrochemical determination of morin (MR). The RGO/[Co(NH₃)₆]³⁺ composite was prepared by a simple sonochemical technique. The as-prepared inorganic complex was characterized using suitable physical and chemical characterization techniques. The as-prepared composite was characterized by scanning electron microscopy, elemental mapping analysis and X-ray diffraction studies. In addition, the electrochemical performance of the fabricated electrode was assessed by the cyclic voltammetry, differential pulse voltammetry and electrochemical impedance spectroscopy studies. Besides, the RGO/[Co(NH₃)₆]³⁺ modified electrode had notable electrocatalytic activity towards the detection of MR. Under the optimized condition, the modified electrode showed excellent linearity ranges, acceptable limit of detection, and high sensitivity of 0.008–72.35 μM, 1.0 nM and 4.326 μA μM⁻¹ cm⁻², respectively. The fabricated electrode exhibited acceptable repeatability, reproducibility and stability. On the other hand, the proposed RGO/[Co(NH₃)₆]³⁺ modified electrodes have been applied for the detection of MR in fruit samples, and the results reveal adequate recovery.