A new electrochemical sensing platform for determination of diclofenac based on graphenized pencil lead electrode modified with cobalt oxide

Diclofenac (DIC) is a well-known representative of non-steroidal anti-inflammatory drugs (NSAIDs) with strong anti-pyretic, analgesic and anti-inflammatory properties and for the health of human life, it is very necessary to measure it. Therefore, cobalt oxide nanoparticles were used to modify the graphenized pencil lead electrode (GPLE/Cobalt oxide). Field emission scanning electron microscope, elemental analysis, atomic force microscope, raman spectroscopy techniques have been used to characterize the modified electrodes. It was found that the modified electrode exhibited excellent electrocatalytic activity toward the oxidation of DIC, and under the optimised conditions, the linear response range and detection limit were found to be 1-300 and 0.3 µM, respectively using the differential pulse voltammetry method. The proposed sensor was successfully applied to the determination of diclofenac in human serum samples with satisfactory results. As a result, the ease of preparation, low cost, renewability and high electron transfer capability of the fabricated electrode can be useful in the development of electrochemical biosensors and sensors.