Electrochemical performance of 8-hydroxy-2′-deoxyguanosine and its detection at poly(3-methylthiophene) modified glassy carbon electrode

2007 ◽  
Vol 22 (7) ◽  
pp. 1245-1250 ◽  
Author(s):  
Tian-Hua Li ◽  
Wen-Li Jia ◽  
Huai-Sheng Wang ◽  
Ren-Min Liu
2020 ◽  
Vol 12 (1) ◽  
pp. 48-57 ◽  
Author(s):  
Z. Wang ◽  
H.J. Chen ◽  
F.F. Lin ◽  
L. Yan ◽  
Y. Zhang ◽  
...  

Background: Measuring tartaric acid in liquid food, such as fruits or fruit products is of great importance for assessing the quality of the food. Objective: The aim of the research is to obtain polyaniline/Cu bismuthate nanoflake composites by an in-situ polymerization route for the electrochemical detection of tartaric acid. Methods: Polyaniline/Cu bismuthate nanoflake composites were prepared by in-situ aniline polymerizing route in aqueous solution. The obtained products were characterized by X-Ray diffraction (XRD), Transmission Electron Microscopy (TEM) and high-resolution TEM (HRTEM), respectively. The electrochemical performance for tartaric acid detection has been investigated by cyclic voltammetry method using polyaniline/Cu bismuthate nanoflake composites modified glassy carbon electrode. Results: The nanocomposites comprise of tetragonal CuBi2O4 phase. Polyaniline particles with the size of less than 100 nm attach to the surface of the nanoflakes. A pair of quasi-reversible cyclic voltammetry peaks are located at -0.01 V and +0.04 V, respectively at the 20wt.% polyaniline/Cu bismuthate nanoflake composites modified glassy carbon electrode. The limit of detection is 0.58 µM with the linear range of 0.001-2 mM. The linear range increases from 0.005-2 mM to 0.001-2 mM and limit of detection decreases from 2.3 µM to 0.43 µM with increasing the polyaniline content from 10wt.% to 40wt.%. Conclusion: Comparing with the Cu bismuthate nanoflakes modified glassy carbon electrode, polyaniline/ Cu bismuthate nanoflake composites modified glassy carbon electrode shows enhanced electrochemical performance for tartaric acid detection.


2020 ◽  
Vol 16 (4) ◽  
pp. 424-437
Author(s):  
Kubra Ozturk ◽  
Nurgul K. Bakirhan ◽  
Sibel A. Ozkan ◽  
Bengi Uslu

Background:: new and selective electrochemical sensor was developed for the determination of levocetirizine dihydrochloride, which is an antihistaminic drug. Method:: The investigation was performed by using cyclic, differential pulse and square wave voltammetric methods on the β-cyclodextrin modified glassy carbon electrode. It is thereby planned to obtain information about levocetirizine determination and its mechanism. Result:: The efficiency of experimental parameters including pH, scan rate, and accumulation potential and time on the anodic response of levocetirizine dihydrochloride was studied. By employing the developed method and under optimized conditions, the current showed linear dependence with a concentration in the range between 2 × 10-8 M and 6 × 10-6 M in pH 2.0 Britton Robinson (BR) buffer. Conclusion:: The achieved limits of detection and quantification were found as 3.73 × 10-10 M and 1.24 × 10-9 M, respectively. In addition, the possibility of applying the developed sensor for real sample analysis was investigated, so β-cyclodextrin modified glassy carbon electrode was used to determine levocetirizine dihydrochloride in Xyzal® tablet dosage form. Finally, this sensor was successfully applied to the real sample as a selective, simple, reproducible, repeatable electrochemical sensor.


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.


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