Synthesis of NiO nanostructures as electrode materials for the voltammetric determination of epinephrine in the presence of acetaminophen

Background and purpose: Epinephrine, also called noradrenaline, is an important chemical mediator in the central nervous system of mammals. Experimental approach: The hydrothermally synthesized NiO nano­structures were used for the modification of a screen-printed electrode, and they were characterized and used in this work for the voltammetric determination of epinephrine in the presence of acetaminophen. Several electrochemical techniques were employed to investigate the electrochemical properties of NiO-modified screen-printed carbon electrode, including cyclic voltammetry, differential pulse voltammetry and chronoamperometry. Key results: The differential pulse voltammetry peak current of epinephrine was linear with concentration in the range from 0.01 to 400.0 μmol L-1, and the limit of detection was 0.005 μM with a sensitivity of 0.1167 μA L μmol-1. The findings indicated that the current signals for epinephrine were significantly amplified, a result attributed to the superior catalytic performance of the NiO nanostructures. Furthermore, the oxidation peaks for epinephrine and acetaminophen were distinctly separated, with potential differences of approximately 360 mV and 545 mV, respectively. Conclusion: Furthermore, the NiO modified screen-printed carbon electrode was successfully applied to quantify epinephrine and acetamino­phen in both urine samples and pharmaceutical formulations. The results indicated satisfactory recovery rates for the target analytes. Consequently, this electrode is suitable for the analysis of both compounds in pharmaceutical and clinical laboratory settings.