Poly(p-aminobenzene sulfonic acid)-modified glassy carbon electrode for simultaneous detection of dopamine and ascorbic acid

2005 ◽  
Vol 107 (2) ◽  
pp. 528-534 ◽  
Author(s):  
Guiying Jin ◽  
Yuzhong Zhang ◽  
Wangxing Cheng
Keyword(s):  
Ascorbic Acid ◽  
Glassy Carbon Electrode ◽  
Glassy Carbon ◽  
Sulfonic Acid ◽  
Simultaneous Detection ◽  
Carbon Electrode ◽  
Modified Glassy Carbon Electrode

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

2020 ◽  
Vol 16 (4) ◽  
pp. 393-403 ◽  
Author(s):  
Renjini Sadhana ◽  
Pinky Abraham ◽  
Anithakumary Vidyadharan
Keyword(s):  
Cyclic Voltammetry ◽  
Graphene Oxide ◽  
Glassy Carbon Electrode ◽  
Glassy Carbon ◽  
Simultaneous Detection ◽  
Differential Pulse ◽  
Carbon Electrode ◽  
Modified Glassy Carbon Electrode ◽  
Reduced Graphene ◽  
Pulse Voltammetry

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.

scholarly journals Electrochemical antioxidant screening and evaluation based on guanine and chitosan immobilized MoS2 nanosheet modified glassy carbon electrode (guanine/CS/MoS2/GCE)

2020 ◽  
Vol 18 (1) ◽  
pp. 1-9 ◽  
Author(s):  
Ping Tang ◽  
Xiaosheng Tang ◽  
Shiyong Mei ◽  
Yixi Xie ◽  
Liangliang Liu ◽  
...  
Keyword(s):  
Ascorbic Acid ◽  
Antioxidant Capacity ◽  
Glassy Carbon Electrode ◽  
Glassy Carbon ◽  
Carbon Electrode ◽  
Oxidation Peak ◽  
Modified Glassy Carbon Electrode ◽  
Peak Current ◽  
Oxidation Peak Current ◽  
Antioxidant Capacities

AbstractIn this study, an electrochemical biosensor based on guanine and chitosan immobilized MoS2 nanosheet modified glassy carbon electrode (guanine/CS/MoS2/GCE) was developed and employed for antioxidant screening and antioxidant capacity evaluation. The oxidation peak current of guanine was improved and nearly tripled after modifications of chitosan and MoS2 nanosheet. The immobilized guanine could be damaged by hydroxyl radicals generated in Fenton solution. However, in the presence of antioxidants, the guanine was protected and the oxidation peak current of guanine increased. This process mimics the mechanism of antioxidant protection in human body. The factors affecting preparation of sensor and detection of antioxidant capacity were optimized. At the optimum conditions, the guanine/CS/MoS2/GCE showed wide linear range, low detection limit, satisfactory reproducibility and stability for detection. Ascorbic acid was used as a model antioxidant to evaluate the antioxidant capacity. A good linearity was observed with a correlation coefficient of 0.9959 in the concentrations between 0.5 and 4.0 mg L-1. The antioxidant capacities of three flavonoids were also tested and the rank of antioxidant capacities was ascorbic acid (51.84%), quercetin (45.82%), fisetin (34.39%) and catechin (16.99%). Due to the rapid measurement and low cost, this sensor could provide an available sensing platform for antioxidant screening and evaluation.

Sign in / Sign up

Export Citation Format

Share Document