Electrografting and Surface Properties of Some Substituted Nitrophenols on Glassy Carbon Electrode and Simultaneous Pb2+- Cd2+Analysis via Assist of Graphene Oxide Terminated Surface

2014 ◽  
Vol 161 (10) ◽  
pp. H696-H704 ◽  
Author(s):  
Aslı Erkal ◽  
Mehmet Selçuk Erdoğan ◽  
İhsan Aşık ◽  
Haslet Ekşi ◽  
Seungwon Jeon ◽  
...  
2020 ◽  
Vol 16 (4) ◽  
pp. 393-403 ◽  
Author(s):  
Renjini Sadhana ◽  
Pinky Abraham ◽  
Anithakumary Vidyadharan

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.


The Analyst ◽  
2019 ◽  
Vol 144 (6) ◽  
pp. 1960-1967 ◽  
Author(s):  
Chao Chen ◽  
Pengcheng Zhao ◽  
Meijun Ni ◽  
Chunyan Li ◽  
Yixi Xie ◽  
...  

A temperature-induced sensing film consisting of poly(N-vinylcaprolactam) (PVCL), graphene oxide (GO) and glucose oxidase (GOD) was fabricated and used to modify a glassy carbon electrode (GCE).


The Analyst ◽  
2018 ◽  
Vol 143 (1) ◽  
pp. 297-303 ◽  
Author(s):  
Yang Gao ◽  
Xiufeng Wu ◽  
Hui Wang ◽  
Wenbo Lu ◽  
Mandong Guo

The highly sensitive and selective electrochemical sensor of hesperidin based on gold nanoparticles (AuNPs) and reduced graphene oxide (rGO) modified glassy carbon electrode (GCE) is reported.


2018 ◽  
Vol 3 (1) ◽  
pp. 1 ◽  
Author(s):  
Jésica Pereyra ◽  
María Martinez ◽  
Cesar Barbero ◽  
Mariano Bruno ◽  
Diego Acevedo

The detection of dopamine, an important neurotransmitter in the central nervous system, is relevant because low levels of dopamine can cause brain disorders. Here, a novel electrochemical platform made of a hydrogel–graphene oxide nanocomposite was employed to electrochemically determine simultaneously dopamine (DA) and ascorbic acid (AA). Unlike previous work, where the base electrode is modified, the active material (graphene oxide, GO) was dispersed in the hydrogel matrix, making an active nanocomposite where the electrochemical detection occurs. The GO, hydrogel and nanocomposite synthesis is described. Dynamic Light Scattering, UV-visible and FTIR spectroscopies showed that the synthesized GO nanoparticles present 480 nm of diagonal size and a few sheets in height. Moreover, the polymer swelling, the adsorption capacity and the release kinetic of DA and AA were evaluated. The nanocomposite showed lower swelling capacity, higher DA partition coefficient and faster DA release rate than in the hydrogel. The electrochemical measurement proved that both materials can be employed to determine DA and AA. Additionally, the nanocomposite platform allowed the simultaneous determination of both molecules showing two well separated anodic peaks. This result demonstrates the importance of the incorporation of the nanomaterial inside of the hydrogel and proves that the nanocomposite can be used as a platform in an electrochemical device to determinate DA using an unmodified glassy carbon electrode.


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