scholarly journals Highly Sensitive Detection of Dopamine at Ionic Liquid Functionalized RGO/ZIF-8 Nanocomposite-Modified Electrode

2019 ◽  
Vol 2019 ◽  
pp. 1-9 ◽  
Author(s):  
Lei Cheng ◽  
Youjun Fan ◽  
Xingcan Shen ◽  
Hong Liang
Keyword(s):  
Ionic Liquid ◽  
Modified Electrode ◽  
Electrocatalytic Activity ◽  
Electrochemical Impedance ◽  
Modified Electrodes ◽  
Differential Pulse ◽  
Zeolitic Imidazolate Framework ◽  
Response Range ◽  
Highly Sensitive ◽  
Highly Sensitive Detection

A hybrid and hierarchical nanocomposite was successfully prepared by the growth of zeolitic imidazolate framework-8 (ZIF-8) on the template of ionic liquid (IL, [Bmim][BF4]) functionalized reduced graphene oxide (IL-RGO). The structure and morphology of the IL-RGO/ZIF-8 nanocomposite were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared spectrometer (FTIR), and Raman spectroscopy. The results showed that RGO sheets were refrained from restacking by IL, and ZIF-8 nanoparticles grew well on the surface of IL-RGO. Owing to the synergistic effect from large surface area and excellent electrocatalytic activity of ZIF-8 and great electrical conductivity of IL-RGO, a highly sensitive sensor for dopamine (DA) can be obtained. IL-RGO/ZIF-8-modified electrode exhibits good electrocatalytic activity and electroconductive properties towards DA which were investigated by cyclic voltammetry (CV), differential pulse voltammetry (DPV), and electrochemical impedance spectroscopy (EIS). Compared with bare or IL-RGO-modified electrodes, the IL-RGO/ZIF-8-modified electrode effectively depressed the oxidation overpotential of DA. The linear response range of DA was from 1.0×10−7 to 1.0×10−4 mol/L with a low detection of limit 3.5×10−8 mol/L. In addition, the sensor was shown to provide satisfactory stability for the determination of DA.

scholarly journals Novel Electrochemical Sensor Fabricated for Individual and Simultaneous Ultrasensitive Determination of Olaquindox and Carbadox Based on MWCNT-OH/CMK-8 Hybrid Nanocomposite Film

Molecules ◽  
2019 ◽  
Vol 24 (17) ◽  
pp. 3041 ◽  
Author(s):  
Yanqing Liu ◽  
Gengxin Hu ◽  
Hongwu Wang ◽  
Su Yao ◽  
Yinjian Ye
Keyword(s):  
Electrochemical Sensor ◽  
Simultaneous Determination ◽  
Modified Electrode ◽  
Electrochemical Impedance ◽  
Modified Electrodes ◽  
Differential Pulse ◽  
Hybrid Nanocomposite ◽  
Experimental Conditions ◽  
Linear Relationships

A hybrid nanocomposite consisting of hydroxylated multi-walled carbon nanotubes (MWCNTs−OH) and cube mesoporous carbon (CMK−8) was applied in this study to construct an MWCNT−OH/CMK−8/gold electrode (GE) electrochemical sensor and simultaneously perform the electro-reduction of olaquindox (OLA) and carbadox (CBX). The respective peak currents of CBX and OLA on the modified electrode increased by 720- and 595-fold relative to the peak current of GE. The performances of the modified electrode were investigated with electrochemical impedance spectroscopy, cyclic voltammetry, and differential pulse voltammetry. Then, the modified electrodes were used for the individual and simultaneous determination of OLA and CBX. The fabricated sensor demonstrated a linear response at 0.2–500 nmol/L in optimum experimental conditions, and the detection limits were 104.1 and 62.9 pmol/L for the simultaneous determination of OLA and CBX, respectively. As for individual determination, wide linear relationships were obtained for the detected OLA with levels of 0.05–500 nmol/L with LOD of 20.7 pmol/L and the detected CBX with levels of 0.10–500 nmol/L with LOD of 50.2 pmol/L. The fabricated sensor was successfully used in the independent and simultaneous determination of OLA and CBX in spiked pork samples.

scholarly journals Carbon nanotube-ionic liquid nanocomposite modified carbon-ceramic electrode for determination of dopamine in real samples

2013 ◽  
Vol 11 (7) ◽  
pp. 1172-1186 ◽  
Author(s):  
Mir Majidi ◽  
Reza Baj ◽  
Abdolhossein Naseri
Keyword(s):  
Ionic Liquid ◽  
Carbon Nanotube ◽  
Modified Electrode ◽  
Electrochemical Impedance ◽  
Differential Pulse ◽  
Selective Determination ◽  
Carbon Ceramic Electrode ◽  
Electro Oxidation ◽  
Carbon Ceramic

AbstractRoom temperature 1-butyl-3-methylimidazolium tetraflouroborate ([BMIM][BF4]) ionic liquid was employed for dispersion of multi walled carbon nanotubes (MWCNTs) and the formation of nanocomposite on the surface of a carbon-ceramic electrode. The surface of the modified electrode was characterized using scanning electron microscopy and electrochemical impedance spectroscopy. The modified electrode exhibited excellent electrochemical activity to oxidation of dopamine (DA); whereas electro oxidation of ascorbic acid (AA) was not seen and electro oxidation of uric acid (UA) appeared at a more positive potential than DA. The multi walled carbon nanotube-ionic liquid nanocomposite modified carbon-ceramic electrode was used for the selective determination of DA in the presence of high levels of AA and UA using differential pulse voltammetry. The calibration curve for DA was linear in the range of 3.00 to 130 µM with the detection limit (S/N=3) of 0.87 µM. The present electrode was successfully applied to the determination of DA in some commercial pharmaceutical samples and human blood serum.

The electrocatalytic response of metallophthalocyanines when clicked to electrodes and to nanomaterials

2021 ◽  
Author(s):  
◽  
Lekhetho Simon Mpeta
Keyword(s):  
Hydrogen Peroxide ◽  
Silver Nanoparticles ◽  
Zinc Oxide ◽  
Photoelectron Spectroscopy ◽  
Electrocatalytic Activity ◽  
Electrochemical Impedance ◽  
Modified Electrodes ◽  
Transmission Electron ◽  
Reduced Graphene ◽  
Electrochemical Microscopy

Conjugates of nanomaterials and metallophthalocyanines (MPcs) have been prepared and their electrocatalytic activity studied. The prepared nanomaterials are zinc oxide and silver nanoparticles, reduced graphene oxide nanosheets and semiconductor quantum dots. The MPcs used in this work are cobalt (II) (1a), manganese(III) (1b) and iron (II) (1c) 2,9(10),16(17),23(24)- tetrakis 4-((4-ethynylbenzyl) oxy) phthalocyaninato, 2,9(10),16(17),23(24)- tetrakis(5-pentyn-oxy) cobalt (II) phthalocyaninato (2), 9(10),16(17),23(24)- tris-[4-tert-butylphenoxy)-2- (4-ethylbezyl-oxy) cobalt (II) phthalocyaninato (3), 9(10),16(17),23(24)- tris-[4-tertbutylphenoxy)-2-(pent-4yn-yloxy)] cobalt (II) phthalocyaninato (4), cobalt (II) (5a) and manganese (III) (5b) 2,9(10),16(17),23(24)- tetrakis [4-(4-(5-chloro-1H-benzo [d]imidazol-2-yl)phenoxy] phthalocyaninato and 9(10),16(17),23(24)- tris tert butyl phenoxy- 2- [4-(4-(5-chloro-1H-benzo[d]imidazole-2-yl)phenoxy] cobalt (II) phthalocyaninato (6). Some of these MPcs (1a, 3 and 4) were directly clicked on azide grafted electrode, while some (1b, 1c, 2, 5a and 5b) were clicked to azide functionalised nanomaterials and then drop-dried on the electrodes. One phthalocyanine (5b) was drop-dried on the electrode then silver nanoparticles were electrodeposited on it taking advantage of metal-N bond. Scanning electrochemical microscopy, voltammetry, chronoamperometry, electrochemical impedance spectroscopy are among electrochemical methods used to characterise modified electrodes. Transmission electron microscopy, X-ray photoelectron spectroscopy, Xray diffractometry, Raman spectroscopy and infrared spectroscopy were employed to study surface functionalities, morphology and topography of the nanomaterials and complexes. Electrocatalytic activity of the developed materials were studied towards oxidation of 2-mercaptoethanol, hydrazine and hydrogen peroxide while the reduction study was based on oxygen and hydrogen peroxide. In general, the conjugates displayed superior catalytic activity when compared to individual materials. Complex 2 alone and when conjugated to zinc oxide nanoparticles were studied for their nonlinear optical behaviour. And the same materials were explored for their hydrazine detection capability. The aim of this study was to develop sensitive, selective and affordable sensors for selected organic waste pollutants. Conjugates were found to achieve the aim of the study compared to when individual materials were employed.

scholarly journals Highly sensitive detection of hexavalent chromium utilizing a sol-gel/carbon nanotube modified electrode

2016 ◽  
Vol 781 ◽  
pp. 120-125 ◽  
Author(s):  
Samuel M. Rosolina ◽  
Stefanie A. Bragg ◽  
Ruizhuo Ouyang ◽  
James Q. Chambers ◽  
Zi-Ling Xue
Keyword(s):  
Carbon Nanotube ◽  
Hexavalent Chromium ◽  
Modified Electrode ◽  
Sol Gel ◽  
Sensitive Detection ◽  
Highly Sensitive ◽  
Highly Sensitive Detection

Electrocatalytic activity of C-dots for highly sensitive detection of Uric acid

2019 ◽  
Vol 14 ◽  
pp. 545-552
Author(s):  
T. Dhanasekaran ◽  
A. Padmanaban ◽  
G. Gnanamoorthy ◽  
S. Praveen Kumar ◽  
A. Stephen ◽  
...  
Keyword(s):  
Uric Acid ◽  
Electrocatalytic Activity ◽  
Sensitive Detection ◽  
Highly Sensitive ◽  
Highly Sensitive Detection

An Amperometric Immunosensor for α-Fetoprotein Based on Antibody Coated Nano ZrO2-Au-Poly Lysine Composite Membrane Modified Electrode

2011 ◽  
Vol 343-344 ◽  
pp. 490-496 ◽  
Author(s):  
Yuan Zhao Wu ◽  
Fu Tao Hu ◽  
Ning Gan ◽  
Jian Guo Hou ◽  
Tian Hua Li ◽  
...  
Keyword(s):  
Modified Electrode ◽  
Composite Membrane ◽  
Electrochemical Impedance ◽  
Signal To Noise Ratio ◽  
Cost Effective ◽  
Differential Pulse ◽  
Phenoxyacetic Acid ◽  
Serum Samples ◽  
Amperometric Immunosensor ◽  
Sensitivity And Selectivity

One novel amperometric immunosensor for α-fetop- rotein was fabricated which was modified by antibody immobilized on nano ZrO2-Au-polyLysine composite membrane. Firstly, the deoxyribonucleic acid – phenoxyacetic acid isoniazid- Schiff base Co(II) complex (DNA-CoL) mixture film was casted on surface of multi carbon nanotubes(MWCNTs) modified glassy carbon electrode(GCE/CNTs/DNA-CoL). Then the composite nanoparticles (ZrO2-Au-pLL) was employed to immobilize the antibody of α-fetoprotein(AFP) to produce the probes(ZrO2-Au-pLL-anti AFP) for AFP. Finally the probes were modified on GCE/CNTs/DNA-CoL through the specific connection between DNA and ZrO2 to form a novel nanocomposite membrane immunosensor for AFP(GCE/CNTs/ DNA-CoL/ZrO2-Au–pLL-anti AFP). The function of immunosensor was investigated by scanning electron microscopy (SEM), cyclic voltammetry(CV), differential pulse voltammety (DPV) and electrochemical impedance spectroscopy experiment (EIS). The results indicated that combining the advantages of the MWNTs-DNA material and ZrO2-Au-pLL-anti AFP nano probes, the immunosensor with excellent sensitivity and selectivity to AFP was prepared successfully. The modified electrode was sensitive to AFP with a linear relationship between 0.05 and 10 ng · mL−1 and a correl- ation coefficient of 0.9905. The detection limit at a signal to noise ratio of 3 was 0.01 ng·mL−1 under the optimal conditions. The described immunosensor preparation and immunoassay methods offer promise for simple and cost-effective analysis of AFP in serum samples.

Highly Sensitive Electrochemical Sensor for the Detection of Chloramphenicol Based on Biomass Derived Porous Carbon

2020 ◽  
Vol 12 (3) ◽  
pp. 376-382 ◽  
Author(s):  
Guoping Wang ◽  
NuerbiYayalikun ◽  
Xamxikamar Mamat ◽  
Yongtao Li ◽  
Xun Hu ◽  
...  
Keyword(s):  
Electrochemical Sensor ◽  
Porous Carbon ◽  
Modified Electrodes ◽  
Differential Pulse ◽  
Reduction Peak ◽  
Active Electrode ◽  
Carbon Doped ◽  
Free Process ◽  
Highly Sensitive ◽  
Voltammetry Methods

In this study, the method for detection of chloramphenicol was investigated by electrochemical sensor; the sensor was constructed by biomass derived porous carbon. At first, porous carbon doped with hetroatoms (nitrogen, sulfur, phosphorus) was synthesized based on the use of pyrolysis and high temperature carbonization methods. Elaeagnusangustifolia L. gum was used as the carbon source in the facile template-free process. The biomass derived porous carbon was then used as the active electrode material for antibiotic sensing. The chemically modified electrodes properties were studied with the cyclic voltammetry and differential pulse voltammetry methods. The effects of the scan rate, accumulation time and pH, were carefully considered. Comparison with other working electrodes at the optimized conditions indicated that the N, S, P triple doped porous carbon modified glassy carbon electrode appeared a well-defined reduction peak towards chloramphenicol. The linear concentration response of chloramphenicol ranged from 1 to 40 μM (R=0.9903) and 50 to 500 μM (R=0.9923), and a low detection limit of 0.01 μM (S/N=3). Furthermore, the constructed novel electrochemical sensor was used for detection of chloramphenicol in real samples and achieved satisfactory recovers.

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