Eu(2)O(3)@Cr(2)O(3) Nanoparticles-Modified Carbon Paste Electrode for Efficient Electrochemical Sensing of Neurotransmitters Precursor L-DOPA

There are ten million people in the world who have Parkinson’s disease. The most potent medicine for Parkinson’s disease is levodopa (L-DOPA). However, long-term consumption of L-DOPA leads to the appearance of side effects, as a result of which the control and monitoring of its concentrations are of great importance. In this work, we have designed a new electrochemical sensor for detecting L-DOPA using a carbon paste electrode (CPE) modified with Eu(2)O(3)@Cr(2)O(3) composite nanoparticles. Rare earth elements, including Eu, are increasingly used to design new electrode nanocomposites with enhanced electrocatalytic properties. Europium has been considered a significant lanthanide element with greater redox reaction behavior. We conducted a hydrothermal synthesis of Eu(2)O(3)@Cr(2)O(3) and, for the first time, the acquired nanoparticles were used to modify CPE. The proposed Eu(2)O(3)@Cr(2)O(3)/CPE electrode was investigated in terms of its electrocatalytic properties and then used to develop an analytical method for detecting and quantifying L-DOPA. The proposed sensor offers a wide linear range (1–100 µM), high sensitivity (1.38 µA µM(−1) cm(−2)) and a low detection limit (0.72 µM). The practical application of the proposed sensor was investigated by analyzing commercially available pharmaceutical tablets of L-DOPA. The corresponding results indicate the excellent potential of the Eu(2)O(3)@Cr(2)O(3)/CPE sensor for application in real-time L-DOPA detection.