Voltammetric determination of pyrazinamide at graphene-zinc oxide nanocomposite modified carbon paste electrode employing differential pulse voltammetry

• A simple, sensitive and selective voltammetric sensor for PZN by using a carbon paste electrode modified with graphene and zinc oxide was introduced.
• Wide linear working range, good reproducibility, fast response and high stability were the main advantages of the proposed sensor.
• The sensor was used successively for analysis of PZN in pharmaceutical formulations, urine and blood serum samples.
• Lowest limit of detection obtained for PZN.

Pyrazinamide (PZN) also called as Pyrazinecarboxamide is a widely used drug for the treatment of Tuberculosis. In the present work, we proposed a sensitive method for determination of PZN using Graphene–Zinc oxide-Carbon paste electrode (GNS-ZnO-CPE). The surface characterization of electrode materials was done by using X-Ray diffraction, Scanning electron microscopy, Energy dispersive X-ray spectroscopy and transmission electron microscopy. The electrocatalytic response of PZN at GNS-ZnO-CPE was measured using cyclic voltammetry (CV), differential pulse voltammetry (DPV) and electrochemical impedance spectroscopy (EIS). In addition, electrochemical impedance studies revealed that the smaller Rct value was observed at GNS-ZnO-CPE as compared to that of CPE, which authenticates its good conductivity. Under the optimized conditions, Ip (μA) was proportional to PZN concentration in the range of 1.5 × 10−7 to 4.0 × 10−4 M with a detection limit of 4.31 × 10−8 M. The proposed electrochemical sensor showed excellent recovery in pharmaceutical formulations, urine and blood serum samples which revealed the promising practicality of sensor for PZN detection.

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