Solar Exfoliated Graphene Oxide: A Platform for Electrochemical Sensing of Epinephrine

Abstract

Introduction: In this study, solar exfoliated graphite oxide modified glassy carbon electrode was used for the anodic oxidation of epinephrine in a phosphate buffer medium at pH7. The modified electrode showed fast response and sensitivity towards Epinephrine Molecule (EP). The electrode was characterized electrochemically through Cyclic Voltammetry (CV) and Differential Pulse Voltammetry (DPV). Area of the electrode enhanced three times during modification and studies reveal that the oxidation process of EP occurs by an adsorption controlled process involving two electrons. The results showed a detection limit of 0.50 ± 0.01μM with a linear range up to 100 μM. The rate constant calculated for the electron transfer reaction is 1.35 s-1. The electrode was effective for simultaneous detection of EP in the presence of Ascorbic Acid (AA) and Uric Acid (UA) with well-resolved signals. The sensitivity, selectivity and stability of the sensor were also confirmed. Methods: Glassy carbon electrode modified by reduced graphene oxide was used for the detection and quantification of epinephrine using cyclic voltammetry and differential pulse voltammetry. Results: The results showed an enhancement in the electrocatalytic oxidation of epinephrine due to the increase in the effective surface area of the modified electrode. The anodic transfer coefficient, detection limit and electron transfer rate constant of the reaction were also calculated. Conclusion: The paper reports the determination of epinephrine using reduced graphene oxide modified glassy carbon electrode through CV and DPV. The sensor exhibited excellent reproducibility and repeatability for the detection of epinephrine and also its simultaneous detection of ascorbic acid and uric acid, which coexist in the biological system.

A Nanocomposite Containing Carbon Nano‐onions and Polyaniline Nanotubes as a Novel Electrode Material for Electrochemical Sensing of Daidzein

“…Further functionalization of the CNOs was conducted according to the procedure proposed by Giordani et al [53]. Benzylamine and amyl nitrite were added to the pristine CNOs in DMF, and the reaction was performed under an inert N 2 atmosphere.…”

“…Electrode reaction rate constant k s for DA is calculated as 1.17 � 0.06 s À 1 and can be compared with k s values for compounds from isoflavones group such as rutin (1.59 s À 1 ) [51], puerarin (1.72 s À 1 ) [52] or other with a similar structure like epinephrine (1.35 s À 1 ) [53]. The formal standard potential for DA oxidation E pa o (+ 0.65 V) was determined by extrapolation of the linear regression curve for the relation E pa vs. v (Figure 5D).…”