Praseodymium molybdate nanoplates/reduced graphene oxide nanocomposite based electrode for simultaneous electrochemical determination of entacapone, levodopa and carbidopa

Entacapone is a prescription commonly used in combination with other medications for the treatment of Parkinson’s disease. Entacapone together with levodopa and carbidopa causes levodopa to have a longer effect in the brain. The objective of this work is using a new nanocomposite electrode based on praseodymium molybdate nanoplates/reduced graphene oxide for simultaneous determination of entacapone (EN), levodopa (LD) and carbidopa (CD). This nanocomposite was synthesized for the first time with two theoretical mass ratio through a facile sonochemical method and be characterized through FE-SEM, X-ray diffraction and FT-IR techniques. Mass ratio of 2:1 (PrMoOG2) was selected as the optimum ratio and used to conduct all determinations. Differential pulse voltammetry technique was used to carry out electrochemical determinations in 0.1 M PBS solution (pH 3.0) as supporting electrolyte. The detection limit of suggested modified electrode was 3.18 × 10⁻¹⁰ M for EN, 3.39 × 10⁻⁸ M for LD and 1.66 × 10⁻⁸ M for CD. The linear dynamic range of determinations were as follows: 0.009–200 μM for EN, 0.06–900 μM for LD and 0.03–800 μM for CD. To evaluate the validity of the recommended method, a commercial pharmaceutical tablets (Entadoram^® 100 mg) was analyzed. Reproducibility, long life-time and multiple reusability of the electrode besides its detection limits and wide dynamic linear ranges, are the main advantages of the proposed sensor in this study.