Preparation and Characterization of Hemoglobin Immobilized on Graphene Quantum Dots-Chitosan Nanocomposite as a Sensitive and Stable Hydrogen Peroxide Biosensor

2016 ◽  
Vol 14 (7) ◽  
pp. 685-691 ◽  
Author(s):  
Rahim Mohammad-Rezei ◽  
Habib Razmi
Keyword(s):  
Hydrogen Peroxide ◽  
Quantum Dots ◽  
Graphene Quantum Dots ◽  
Hydrogen Peroxide Biosensor

L-cysteine functionalized graphene quantum dots for sub-ppb detection of As (III)

2021 ◽  
Author(s):  
Md. Farhan Naseh ◽  
Neelam Singh ◽  
Jamilur R. Ansari ◽  
Ashavani Kumar ◽  
Tapan Sarkar ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Quantum Dots ◽  
Room Temperature ◽  
Graphene Quantum Dots ◽  
Optical Characterization ◽  
Functionalized Graphene ◽  
Transmission Electron ◽  
Sensitivity And Selectivity ◽  
Structural Characterizations

Abstract Here, we report functionalized graphene quantum dots (GQDs) for the optical detection of arsenic at room temperature. GQDs with the fluorescence of three fundamental colors (red, green, and blue) were synthesized and functionally capped with L-cysteine (L-cys) to impart selectively towards As (III) by exploiting the affinity of L-cys towards arsenite. The optical characterization of GQDs was carried out using UV-Vis absorption spectroscopy, Fourier transform infrared spectroscopy, and fluorescence spectrometry and the structural characterizations were performed using transmission electron microscopy. The fluorescence results showed instantaneous quenching in intensity when the GQDs came in contact with As (III) for all test concentrations over a range from 0.025 ppb to 25 ppb, which covers the permissible limit of arsenic in drinking water. The experimental results suggested excellent sensitivity and selectivity towards As (III).

scholarly journals Synthesis and characterization of graphene quantum dots/cobalt ferrite nanocomposite

2018 ◽  
Vol 310 ◽  
pp. 012139 ◽  
Author(s):  
Shilpa Ramachandran ◽  
M. Sathishkumar ◽  
Nikhil K. Kothurkar ◽  
R. Senthilkumar
Keyword(s):  
Quantum Dots ◽  
Cobalt Ferrite ◽  
Graphene Quantum Dots ◽  
Synthesis And Characterization

scholarly journals Synthesis and Characterization of Polymeric Graphene Quantum Dots Based Nanocomposites for Humidity Sensing

2016 ◽  
Vol 2016 ◽  
pp. 1-6 ◽  
Author(s):  
Lam Minh Long ◽  
Nguyen Nang Dinh ◽  
Tran Quang Trung
Keyword(s):  
Quantum Dots ◽  
Atmospheric Pressure ◽  
Graphene Quantum Dots ◽  
Composite Films ◽  
Fast Response ◽  
Bulk Heterojunctions ◽  
Humidity Sensing ◽  
Best Value ◽  
Doped Graphene

Graphene quantum dots (GQDs) were synthesized and incorporated with polyethylenedioxythiophene:poly(4-styrenesulfonate) (PEDOT:PSS) and carbon nanotube (CNT) to form a composite that can be used for humidity sensors. The 600 nm thick composite films contained bulk heterojunctions of CNT/GQD and CNT/PEDOT:PSS. The sensors made from the composites responded well to humidity in a range from 60 to 80% at room temperature and atmospheric pressure. With a CNT content of 0.4 wt.% (GPC-1) to 0.8 wt.% (GPC-2) and 1.2 wt.% (GPC-3), the sensitivity of the humidity sensing devices based on CNT-doped graphene quantum dot-PEDOT:PSS composites was increased from 4.5% (GPC-1) to 9.0% (GPC-1) and 11.0% (GPC-2), respectively. The fast response time of the GPC sensors was about 20 s and it was much improved due to CNTs doping in the composites. The best value of the recovery time was found to be of 40 s, for the GPC composite film doped with 1.2 wt.% CNT content.

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