Voltammetric determination of carbidopa using a modified glassy carbon electrode with La3+/Co3O4 nanocubics

Carbidopa (CD) is one of the important catecholamine and it is used in the treatment of Parkinson s disease. Carbidopa is a drug given to people with Parkinson’s disease in order to inhibit peripheral metabolism of levodopa. Carbidopa does not cross the blood-brain barrier (BBB) and contributes to the production of effective brain concentrations of dopamine from lower doses of levodopa by inhibiting the peripheral decarboxylation of levodopa to dopamine [1,2]. Therefore, it is very important to establish a sensitive method for detection of carbidopa in pharmaceutical formulations and human serum. Different techniques have been employed for the determination of carbidopa in pharmaceutical formulations. Among of these methods, electrochemical techniques offer the opportunity for portable, economical, sensitive and rapid methodologies. Among many electrodes, glassy carbon electrodes (GCEs), which are stable and robust carbon-based electrodes, have been widely used because of their high biocompatibility, low tendency for surface fouling, and relatively low level of residual current over a wide potential range. Thus, the combination of inorganic nanoparticles and sensors is one of the most exciting areas in modern analytical detection development because they offer excellent prospects for designing highly sensitive and selective sensors. As an important p-type semiconductor, cobalt oxide (Co3O4 in particular) has gained increasing attention because of its applications in many fields, such as sensors, gas sensing, catalysis, and lithium-ion batteries. The combination metals with metal oxide nanocomposites have a significant effect on the 14th Annual Electrochemistry Seminar of Iran Materials and Energy Research Center (MERC), 12- 13 Dec, 2018 45 catalytic activity due to the interactions and surface reactivity [3]. In this study, a new glassy carbon electrode chemically modified with La3+/Co3O4 nanocubics was constructed and used for the sensitive electrochemical determination of trace amounts of carbidopa. This electrochemical sensor responds to carbidopa in the wide linear range of 1.0×10−6 to 7.0×10−4 M. The detection limit of 7.0×10−8 M was obtained at pH 7.0. The proposed sensor was successfully applied for the determination of carbidopa in real samples.