Amperometric sensor for ascorbic acid based on a glassy carbon electrode modified with gold-silver bimetallic nanotubes in a chitosan matrix

2013 ◽  
Vol 181 (1-2) ◽  
pp. 231-238 ◽  
Author(s):  
Penghao Yang ◽  
Xia Gao ◽  
Lisha Wang ◽  
Qi Wu ◽  
Zhichun Chen ◽  
...  
Keyword(s):  
Ascorbic Acid ◽  
Glassy Carbon Electrode ◽  
Glassy Carbon ◽  
Amperometric Sensor ◽  
Carbon Electrode ◽  
Chitosan Matrix ◽  
Gold Silver

Ascorbic acid amperometric sensor using a graphene-wrapped hierarchical TiO2 nanocomposite

2015 ◽  
Vol 69 (5) ◽  
Author(s):  
Li Fu ◽  
Yu-Hong Zheng ◽  
Zhu-Xian Fu
Keyword(s):  
Ascorbic Acid ◽  
Graphene Oxide ◽  
Reduced Graphene Oxide ◽  
Glassy Carbon Electrode ◽  
Glassy Carbon ◽  
Amperometric Sensor ◽  
Carbon Electrode ◽  
Reduced Graphene

AbstractAn ascorbic acid (AA) amperometric sensor was fabricated based on a glassy carbon electrode (GCE) modified with a reduced graphene oxide-wrapped hierarchical TiO

Glassy carbon electrode modified with gold nanoparticles and hemoglobin in a chitosan matrix for improved pH-switchable sensing of hydrogen peroxide

2015 ◽  
Vol 182 (15-16) ◽  
pp. 2461-2468
Author(s):  
Yang Liu ◽  
Liang Shi ◽  
Jin Gong ◽  
Yu-Ting Fang ◽  
Ning Bao ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Gold Nanoparticles ◽  
Glassy Carbon Electrode ◽  
Glassy Carbon ◽  
Carbon Electrode ◽  
Chitosan Matrix

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.

scholarly journals Hydrogel-Graphene Oxide Nanocomposites as Electrochemical Platform to Simultaneously Determine Dopamine in Presence of Ascorbic Acid Using an Unmodified Glassy Carbon Electrode

2018 ◽  
Vol 3 (1) ◽  
pp. 1 ◽  
Author(s):  
Jésica Pereyra ◽  
María Martinez ◽  
Cesar Barbero ◽  
Mariano Bruno ◽  
Diego Acevedo
Keyword(s):  
Ascorbic Acid ◽  
Graphene Oxide ◽  
Glassy Carbon Electrode ◽  
Glassy Carbon ◽  
Active Material ◽  
Electrochemical Measurement ◽  
Release Kinetic ◽  
Carbon Electrode ◽  
Polymer Swelling ◽  
Hydrogel Matrix

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.

scholarly journals Electrochemical determination of ascorbic acid at p-phenylenediamine film-holes modified glassy carbon electrode

2015 ◽  
Vol 80 (9) ◽  
pp. 1161-1175 ◽  
Author(s):  
Bikila Olana ◽  
Shimeles Kitte ◽  
Tesfaye Soreta
Keyword(s):  
Ascorbic Acid ◽  
Detection Limit ◽  
Glassy Carbon Electrode ◽  
Modified Electrode ◽  
Glassy Carbon ◽  
Linear Response ◽  
Modified Electrodes ◽  
Electrochemical Determination ◽  
Carbon Electrode

In this work the determination of ascorbic acid (AA) at glassy carbon electrode (GCE) modified with a perforated film produced by reduction of diazonium generated in situ from p-phenylenediamine (PD) is reported. Holes were intentionally created in the modifier film by stripping a pre-deposited gold nanoparticles. The modified electrodes were electrochemically characterized by common redox probes: hydroquinone, ferrocyanide and hexamineruthenium(III). The cyclic voltammetric and amperometric response of AA using the modified electrodes was compared with that of bare GCE. The bare GCE showed a linear response to AA in the concentration range of 5 mM to 45 mM with detection limit of 1.656 mM and the modified GCE showed a linear response to AA in the concentration range of 5 ?M to 45 ?M with detection limit of 0.123 ?M. The effect of potential intereferents on amperometric signal of AA at the modified GCE was examined and found to be minimal. The inter-electrode reproducibility, stability, and accuracy were determined. The modified electrode showed excellent inter-electrode reproducibility, accuracy and stability. The modified electrode reported is a promising candidate for use in electroanalysis of AA.

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