Voltammetric Determination of Levodopa Using Mesoporous Carbon—Modified Screen-Printed Carbon Sensors

Abstract

Levodopa is a precursor of dopamine, having important beneficial effects in the treatment of Parkinson’s disease. In this study, levodopa was accurately detected by means of cyclic voltammetry using carbon-based (C-SPCE), mesoporous carbon (MC-SPCE) and ordered mesoporous carbon (OMC-SPCE)-modified screen-printed sensors. Screen-printed carbon sensors were initially used for the electrochemical detection of levodopa in a 10−3 M solution at pH 7.0. The mesoporous carbon with an organized structure led to better electroanalysis results and to lower detection and quantification limits of the OMC-SPCE sensor as compared to the other two studied sensors. The range of linearity obtained and the low values of the detection (0.290 µM) and quantification (0.966 µM) limit demonstrate the high sensitivity and accuracy of the method for the determination of levodopa in real samples. Therefore, levodopa was detected by means of OMC-SPCE in three dietary supplements produced by different manufacturers and having various concentrations of the active compound, levodopa. The results obtained by cyclic voltammetry were compared with those obtained by using the FTIR method and no significant differences were observed. OMC-SPCE proved to be stable, and the electrochemical responses did not vary by more than 3% in repeated immersions in a solution with the same concentration of levodopa. In addition, the interfering compounds did not significantly influence the peaks related to the presence of levodopa in the solution to be analyzed.

Cyclic Voltammetry of Screen-Printed Carbon Electrode Coated with Ag-ZnO Nanoparticles in Chitosan Matrix

“…The graph shows us that the scan rate had an influence on the intensity of the anodic and cathodic peaks. The voltammograms recorded of the SPCE for the five cycles and one cycl preset anodic or cathodic peaks; this, in fact, ensures that the buffer and electrod impure [23]. After this measurement, we conducted the CVs for the unchanged the 10 mM potassium ferrocyanide-buffer solution.…”

“…The scan rates of the measured electrode were observed as a pair of well peaks with the same values of anodic and cathodic currents. The redox reactio The voltammograms recorded of the SPCE for the five cycles and on preset anodic or cathodic peaks; this, in fact, ensures that the buffer and ele impure [23]. After this measurement, we conducted the CVs for the uncha the 10 mM potassium ferrocyanide-buffer solution.…”

“…Regarding the uses of screen-printed carbon electrodes produced by different suppliers, Dascalescu used carbon, mesoporous carbon and ordered mesoporous carbon-based electrodes in order to determine the L Dopa compound from Mucuna pruriens seeds using cyclic voltametric determination [23]. In another complex review regarding the serotonin detection from clinical and pharmaceuticals samples, the carbon electrodes were modified with carbon nanotubes, benzofuran, polyalizarin red-S, Nafion/Ni(OH) 2 , graphene oxide and SPE modified with silver and silver selenite nanoparticles [24].…”

Chiral discrimination of l-DOPA vial/d-tryptophan decorated carbon quantum dots

“…These reports encompass various methods such as colorimetric and electrochemical techniques, high-performance liquid chromatography, and spectrophotometry. 8–16 However, it is worth noting that, to the best of our knowledge, no reports have been published on the chiral detection of l -DOPA based on chiral probes. Consequently, there is a pressing need to develop straightforward sensing methods that offer high selectivity and sensitivity for the chiral detection of l -DOPA.…”

Sensitive Detection of Hydroxytyrosol in Extra Virgin Olive Oils with a Novel Biosensor Based on Single-Walled Carbon Nanotubes and Tyrosinase

“…Alternative methods include electrochemical techniques that provide fast and accurate results [ 40 ]. Electrochemical sensors and biosensors have become increasingly diverse both structurally and in the functionalisation of the nanomaterials used as carriers to make determinations as sensitive, selective and easy as possible, using small amounts of samples without the need for complex pre-preparation [ 41 , 42 , 43 , 44 , 45 , 46 ]. The literature provides valuable information on sensitive and selective techniques, sensors and biosensors for the determination of oleuropein, tyrosol and hydroxytyrosol from real samples of VOO [ 47 , 48 , 49 , 50 ].…”