Development of a Carbon Paste Electrode Modified with Reduced Graphene Oxide and an Imidazole Derivative for Simultaneous Determination of Biological Species of N‐acetyl‐L‐cysteine, Uric Acid and Dopamine

Abstract

In this work, the modified carbon paste electrode (CPE) with an imidazole derivative 2‐(2,3 dihydroxy phenyl) 4‐methyl benzimidazole (DHPMB) and reduced graphene oxide (RGO) was used as an electrochemical sensor for electrocatalytic oxidation of N‐acetyl‐L‐cysteine (NAC). The electrocatalytic oxidation of N‐acetyl‐L‐cysteine on the modified electrode surface was then investigated, indicating a reduction in oxidative over voltage and an intensive increase in the current of analyte. The scan rate potential, the percentages of DHPMB and RGO, and the pH solution were optimized. Under the optimum conditions, some parameters such as the electron transfer coefficient (α) between electrode and modifier, and the electron transfer rate constant) ks) in a 0.1 M phosphate buffer solution (pH=7.0) were obtained by cyclic voltammetry method. The diffusion coefficient of species (D) 3.96×10−5 cm2 s−1 was calculated by chronoamperometeric technique and the Tafel plot was used to calculate α (0.46) for N‐ acetyl‐L‐cysteine. Also, by using differential pulse voltammetric (DPV) technique, two linear dynamic ranges of 2–18 µM and 18–1000 µM with the detection limit of 61.0 nM for N‐acetyl‐L‐cysteine (NAC) were achieved. In the co‐existence system of N‐acetyl‐L‐cysteine (NAC), uric acid (UA) and dopamine (DA), the linear response ranges for NAC, UA, and DA are 6.0–400.0 µM, 5.0–50.0 µM and 2.0–20.0 µM, respectively and the detection limits based on (C=3sb/m) are 0.067 µM, 0.246 µM and 0.136 µM, respectively. The obtained results indicated that DHPMB/RGO/CPE is applicable to separate NAC, uric acid (UA) and dopamine (DA) oxidative peaks, simultaneously. For analytic performance, the mentioned modified electrode was used for determination of NAC in the drug samples with acceptable results, and the simultaneous determination of NAC, UA and DA oxidative peaks was investigated in the serum solutions, too.

Investigation of Methanol Behavior at the Designed Electrochemical Sensor based on Ni(II) Complex and Graphene Nanosheets

“…The nickel (II) complex Ni(II)‐MHP used as the modifier was prepared according to the procedure described in the next section . RGO was synthetized as reported in our previous work . Sodium hydroxide and methanol used were of analytical grade from Merck.…”

Tellurite Carbon Paste Sensors: Microscopic Analysis Provides New Insights on the Nature of the Interaction Between the Ionophore and Analytical Species

“…Carbon paste sensors have several advantages over all other solid sensors such as ease of preparation, low cost and ability to get a new and reproducible surface . Different types of carbon materials (graphite (G), carbon black (CB), carbon nanofibers (CNFs), carbon microspheres (CMS), carbon nanotubes (CNTs) and graphene) have been utilized in the fabrication of carbon paste sensors using a variety of methods .…”

Simultaneous electrochemical investigations of dopamine and uric acid by in situ amino functionalized reduced grahene oxide

“…Graphene is extensively studied material due to its extraordinary properties like high surface area, conductivity and high chemical stability. Various methods and facile routes to synthesis of reduced GO namely chemical reduction [20] electrochemical reduction [21] and thermal reduction [22] are frequently adopted for high yields, purity and its application [23][24][25]. Hans Th.…”