Electrocatalytic determination of levodopa in presence of cabergoline using carbon paste electrode modified with graphene quantum dots/2-chlorobenzoyl ferrocene/ionic liquid

Peyman Mohammadzadeh Jahani

doi:10.5599/jese.1133

Abstract

The electrochemical sensor was fabricated for the simultaneous determination of levodopa and cabergoline using carbon paste electrode (CPE) modified with graphene quantum dots (GQD), 2-chlorobenzoyl ferrocene (2CBF) and ionic liquid (IL). Then, the electrochemical behavior of levodopa alone and simultaneously with cabergoline at the surface of GQDs/2CBF/IL/CPE was investigated in phosphate buffer solution (PBS). Under optimal PBS, pH=7 condition, oxidation peak current has been found proportional to levodopa concentration in the range between 0.07 μM and 500.0 μM, with the limit of detection (LOD) of 0.02 μM (S/N=3). Outputs showed that at GQDs/2CBF/IL/CPE surface, the levodopa and cabergoline oxidation peaks are separated by the potential difference of 200 mV. In addition, it was found that this modified electrode possesses acceptable sensitivity, selectivity, stability and repeatability. All these properties were sufficient to allow simultaneous detection of levodopa and cabergoline in real samples at the surface of GQDs/2CBF/IL/CPE. This was supported by the successful application of this electrochemical sensor electrode for the determination of levodopa and cabergoline in urine, serum, and cabergoline tablets.

Highlights

There is a continuously growing interest in electrochemical sensors and bio-sensors for drugs in environmental, food, and agricultural analyses
Electrochemical features of levodopa at the surface of graphene quantum dots (GQD)/2-chlorobenzoyl ferrocene (2CBF)/ionic liquid (IL)/carbon paste electrode (CPE) For studying the electrochemical oxidation behaviour of levodopa, which is pH-dependent reaction according to the oxidation mechanism presented in Scheme 1, finding an optimal pH value would be of high importance for achieving acceptable outputs
CVs of GQDs/2CBF/IL/CPE in blank and levodopa solutions are presented as curves c and f, respectively

Summary

Introduction

There is a continuously growing interest in electrochemical sensors and bio-sensors for drugs in environmental, food, and agricultural analyses. CPE has been modified with all three mentioned materials (ferrocene, GQDs and IL) to form an efficient sensor electrode for detecting and determining levodopa alone or in the presence of cabergoline.

Results

Conclusion