Nanoscale Graphene Doped with Highly Dispersed Silver Nanoparticles: Quick Synthesis, Facile Fabrication of 3D Membrane-Modified Electrode, and Super Performance for Electrochemical Sensing

2016 ◽  
Vol 26 (13) ◽  
pp. 2122-2134 ◽  
Author(s):  
Yang Li ◽  
Panpan Zhang ◽  
Zhaofei Ouyang ◽  
Mingfa Zhang ◽  
Zhoujun Lin ◽  
...  
Sensors ◽  
2021 ◽  
Vol 21 (5) ◽  
pp. 1659
Author(s):  
Nutcha Larpant ◽  
Pramod K. Kalambate ◽  
Tautgirdas Ruzgas ◽  
Wanida Laiwattanapaisal

This paper proposes a combined strategy of using paper-based competitive immunochromatography and a near field communication (NFC) tag for wireless cotinine determination. The glucose oxidase labeled cotinine antibody specifically binds free cotinine in a sample, whereas the unoccupied antibody attached to BSA-cotinine at the test line on a lateral flow strip. The glucose oxidase on the strip and an assistant pad in the presence of glucose generated H2O2 and imposed the Ag oxidation on the modified electrode. This enabled monitoring of immunoreaction by either electrochemical measurement or wireless detection. Wireless sensing was realized for cotinine in the range of 100–1000 ng/mL (R2 = 0.96) in PBS medium. Undiluted urine samples from non-smokers exhibited an Ag-oxidation rate three times higher than the smoker’s urine samples. For 1:8 diluted urine samples (smokers), the proposed paper-based competitive immunochromatography coupled with an enzyme-modified electrode differentiated positive and negative samples and exhibited cotinine discrimination at levels higher than 12 ng/mL. This novel sensing platform can potentially be combined with a smartphone as a reader unit.


ACS Sensors ◽  
2020 ◽  
Author(s):  
Ru-Jia Yu ◽  
Su-Wen Xu ◽  
Soumyadeep Paul ◽  
Yi-Lun Ying ◽  
Ling-Fei Cui ◽  
...  

NANO ◽  
2016 ◽  
Vol 11 (03) ◽  
pp. 1650036 ◽  
Author(s):  
Xinmeng Zhang ◽  
Kezhi Li ◽  
Hejun Li ◽  
Jinhua Lu ◽  
Leilei Zhang

A novel electrochemical sensing platform was constructed based on a facile self-assembly procedure synthetic laminar molybdenum trioxide dihydrate (MoO[Formula: see text]H2O)-graphene composite. Field emission scanning electron microscopy (FESEM), X-ray spectroscopy, X-ray diffraction (XRD) and Raman spectroscopy were employed to characterize the morphology and composition of the MoO[Formula: see text]H2O-graphene composite. As a model molecule, thiourea was utilized to investigate the electrochemical behaviors of the MoO[Formula: see text]H2O-graphene composite modified glass carbon electrode. The results show that the composite modified electrode has higher electron transfer rate than that of graphene modified electrode and bare glass carbon electrode meanwhile the peak currents of it has a good linear relationship with thiourea concentrations in the range of [Formula: see text] ([Formula: see text]) with detection limit of 4.99[Formula: see text][Formula: see text]M ([Formula: see text]). This novel electrochemical sensor exhibits a higher absorption capacity ([Formula: see text][Formula: see text]mol/cm2), a good reproducibility (1.41% relative standard deviation (RSD)), excellent anti-interference and a high stability. These excellent electrochemical properties of the MoO[Formula: see text]H2O-graphene composite are attributed to the loose and porous structure and the synergistic effects between graphene and MoO[Formula: see text]H2O, which make this composite material hold great potential applications for electrochemical sensor.


A modified glassy carbon electrode (GCE) compositing multi-walled carbon nanotubes (MWCNTs), Nafion and bismuth film was prepared and applied for the sensitive detection of trace Pb (II). MWCNTs were dispersed into ethanol by ultrasonication in the presence of Nafion and the nanotubes are coated onto the bare GCE. After that, an extra Nafion adhesion agent is added to the electrode. By the in situ plating, a bismuth film was fabricated on the MWCNTs-NA/GCE, making the desired electrode, MWCNTs-NA-Bi/GCE. The modified electrode was characterized by differential pulse anodic stripping voltammetry, scanning electron microscopy, and cyclic voltammetry. A deposition potential of –1.4 V (vs. Ag/AgCl) and a deposition time of 300 s were applied to the working electrode under stirred conditions after optimizing. Nanotubes and Nafion concentrations and pH were carefully optimized to determine trace lead ions by using the electrode as an electrochemical-sensing platform. Nafion effectively increased the stability and adhesivity of the composite film. The MWCNTs-NA-Bi film modified electrode can remarkably increase the anodic peak current of Pb2+. The sensitivity of MWCNTs-NA-Bi/GCE is 4.35 times higher than that of the bare GCE with bismuth film. The prepared electrode showed excellent stability and reproducibility and can be applied for determination of Pb2+ contained wastewater.


2008 ◽  
Vol 164 (1-2) ◽  
pp. 149-155 ◽  
Author(s):  
Guangfeng Wang ◽  
Wen Wang ◽  
Jianfeng Wu ◽  
Hongying Liu ◽  
Shoufeng Jiao ◽  
...  

2018 ◽  
Vol 4 (10) ◽  
pp. 1531-1542 ◽  
Author(s):  
Archana Aravind ◽  
Maria Sebastian ◽  
Beena Mathew

In this work we present optical, fluorescence and electrochemical sensing of Cr(iii) ions using silver nanoparticles (AgNPs) synthesized by a green method using Lycopersicon esculentum (LE) extract without any surface functionalization.


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