Selective Determination of Levodopa in the Presence of Vitamin B6. Theophylline and Guaifenesin Using a Glassy Carbon Electrode Modified with a Composite of Hematoxylin and Graphene/ZnO

Abstract

An electrode has been developed based on using a composite of hematoxylin/graphene/ZnO nanocomposite to modify a glassy carbon electrode (GCE). The electrode (HGGCE) was tested and found to be applicable for the voltammetric analysis of levodopa in the presence of vitamin B, theophylline and guaifenesin using a 0.1 M phosphate buffer solution (PBS) pH 7 as the solvent. The HGGCE was used as the working electrode in cyclic voltammetry (CV) and square wave voltammetry (SWV) studies on the electrochemical behavior of levodopa at its surface. The results showed a dramatic enhancement in the oxidation current of levodopa and a shift in its oxidation potential towards more negative potentials as opposed to identical tests using bare GCE as the working electrode. The studies showed that the increase in the oxidation current has two linear profiles in two concentration ranges of 0.05 - 90.0 and 90.0 - 1000.0 μM. The detection limit of SWV analysis using the modified electrode was determined to be 0.03 μM (S/N = 3). Further advantages of the methods based on HGGCE include the simple modification procedure of the electrode, as well as its excellent sensitivity and reproducibility. The modified electrode was eventually found to be applicable to the determination of mixtures of levodopa, vitamin B, theophylline and guaifenesin in real samples.

EDTA salt modified carbon paste electrode for square wave voltammetric determination of theophylline in pharmaceutical tablet formulation

“…However, almost all these techniques are known to have several drawbacks including low sensitivity, long analysis time, tedious sample preparation, expensive instruments and maintenance, trained technician, some requiring derivatization procedure before determination, and use of organic solvents inducing environmental pollution [13][14][15]. Compared to the reported conventional methods, electrochemical methods require relatively minimum cost, high sensitivity and swift technique for bio-molecule detection [14,[16][17][18][19].…”

Treated Screen Printed Electrodes Based on Electrochemically Reduced Graphene Nanoribbons for the Sensitive Voltammetric Determination of Dopamine in the Presence of Uric Acid

“…As shown in the previous studies, graphene nanostructures have been significantly considered in the scientific fields. Researchers demonstrated numerous applications in electrochemical sensor technology because of their large ratio of the surface area to the volume, excellent electrocatalytic characteristics, and high electron transfer kinetics [16,17]. Recent studies strongly focused on the graphene nanoribbons (GNRs), narrow and straight edged stripes of graphene with edge dependent features as the alternative to replace the graphene nanosheets [18].…”