Microwave-Assisted Synthesis of Unmodified Gold Nanoparticles for Colorimetric Detection of Dopamine

2017 ◽  
Vol 730 ◽  
pp. 167-171 ◽  
Author(s):  
Ekarat Detsri ◽  
Kanrayasiri Kamhom ◽  
Chatsuda Detsri
Keyword(s):  
Gold Nanoparticles ◽  
Sodium Citrate ◽  
Limit Of Detection ◽  
Signal To Noise Ratio ◽  
Chemical Reduction ◽  
Colorimetric Detection ◽  
Random Coil ◽  
Microwave Assisted Synthesis ◽  
Microwave Assisted ◽  
Transmission Electron

Unmodified gold nanoparticles (AuNPs) have been successfully synthesized by the chemical reduction of tetrachloride gold (III) ions ([AuCl4]-) in the presence of sodium citrate based on the rapid microwave−assisted approach. The diameter of the synthesized nanoparticles was found in the range of 16.50±2.75 nm. The AuNPs were characterized using UV−vis spectrophotometer, zeta potential analyzer and transmission electron microscope (TEM). The sodium citrate protected AuNPs were found to be selective and sensitive for the detection of dopamine. It was based on the aggregation change of the nanoparticles from random coil to hairpin structure upon the addition of dopamine concentration. The red shift of the plasmonic peak wavelength of AuNPs could be used for the detection of dopamine. The response to dopamine allows for a linear range from 10 to 125 mg⋅L-1 (R2 = 0.9804) with a limit of detection (LOD) at a signal to noise ratio of 3 of 12.85±1.38 mg⋅L-1. The colorimetric sensor was evaluated with 98.0−99.9% recovery of added dopamine in urine sample. The proposed sensor was successfully applied to the determination of dopamine in biological samples.

Electrooxidation of Methanol on Carbon Supported Gold Nanoparticles

2013 ◽  
Vol 313-314 ◽  
pp. 232-236
Author(s):  
Dan Zhang
Keyword(s):  
Gold Nanoparticles ◽  
Catalytic Activity ◽  
Competitive Adsorption ◽  
Chemical Reduction ◽  
Reduction Process ◽  
Carbon Support ◽  
Transmission Electron ◽  
Supported Gold Nanoparticles ◽  
Supported Gold

Activated carbon supported gold nanoparticles (Au/C) were prepared by a chemical reduction process using NaBH4as a reducing agent. The characterization of transmission electron microscope indicated that the Au nanoparticles (AuNPs) in the Au/C catalyst were highly well dispersed on the carbon support. The catalytic activity of the Au/C catalyst for the methanol electrooxidation (MEO) was investigated by the cyclic voltammetry (CV). The results displayed that the Au/C catalyst exhibited a favorable catalytic activity towards the MEO in alkaline solution. Moreover, the competitive adsorption between OH-and CH3OH on the surface of the AuNPs in the Au/C catalyst existed in the course of the MEO. Based on this competitive adsorption, the mechanism of the MEO on the Au/C catalyst was further investigated.

Microwave assisted synthesis of gold nanoparticles and their antibacterial activity against Escherichia coli (E. coli)

2011 ◽  
Vol 11 (1) ◽  
pp. S360-S363 ◽  
Author(s):  
Nishat Arshi ◽  
Faheem Ahmed ◽  
Shalendra Kumar ◽  
M.S. Anwar ◽  
Junqing Lu ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Gold Nanoparticles ◽  
Antibacterial Activity ◽  
Microwave Assisted Synthesis ◽  
E Coli ◽  
Microwave Assisted

scholarly journals Recent Trends in the Microwave-Assisted Synthesis of Metal Oxide Nanoparticles Supported on Carbon Nanotubes and Their Applications

2012 ◽  
Vol 2012 ◽  
pp. 1-15 ◽  
Author(s):  
Sarah C. Motshekga ◽  
Sreejarani K. Pillai ◽  
Suprakas Sinha Ray ◽  
Kalala Jalama ◽  
Rui. W. M. Krause
Keyword(s):  
Carbon Nanotubes ◽  
Metal Oxides ◽  
Chemical Reduction ◽  
Metal Oxide Nanoparticles ◽  
Power Input ◽  
Metal Nanoparticle ◽  
Microwave Assisted Synthesis ◽  
Microwave Assisted ◽  
Coated Metal ◽  
Size And Morphology

The study of coating carbon nanotubes with metal/oxides nanoparticles is now becoming a promising and challenging area of research. To optimize the use of carbon nanotubes in various applications, it is necessary to attach functional groups or other nanostructures to their surface. The combination of the distinctive properties of carbon nanotubes and metal/oxides is expected to be applied in field emission displays, nanoelectronic devices, novel catalysts, and polymer or ceramic reinforcement. The synthesis of these composites is still largely based on conventional techniques, such as wet impregnation followed by chemical reduction of the metal nanoparticle precursors. These techniques based on thermal heating can be time consuming and often lack control of particle size and morphology. Hence, there is interest in microwave technology recently, where using microwaves represents an alternative way of power input into chemical reactions through dielectric heating. This paper covers the synthesis and applications of carbon-nanotube-coated metal/oxides nanoparticles prepared by a microwave-assisted method. The reviewed studies show that the microwave-assisted synthesis of the composites allows processes to be completed within a shorter reaction time with uniform and well-dispersed nanoparticle formation.

Microwave-assisted synthesis of silver nanorods

2004 ◽  
Vol 19 (2) ◽  
pp. 469-473 ◽  
Author(s):  
Fu-Ken Liu ◽  
Pei-Wen Huang ◽  
Yu-Cheng Chang ◽  
Fu-Hsiang Ko ◽  
Tieh-Chi Chu
Keyword(s):  
Sodium Citrate ◽  
Heating System ◽  
Microwave Assisted Synthesis ◽  
Closed Chamber ◽  
Silver Nanorods ◽  
Nanoparticle Growth ◽  
Microwave Assisted ◽  
Judicious Choice ◽  
Key Aspects ◽  
Silver Metal

Described is a method for preparing crystalline silver nanorods in water, in the absence of a surfactant or polymer to direct nanoparticle growth, and without externally added seed crystallites. The procedure used is one in which a silver salt is reduced to silver metal by sodium citrate under the influence of microwave irradiation. Key aspects for the production of these nanorods are the use of a closed-chamber microwave heating system that allows precise temperature control and judicious choice of the citrate concentration. This novel finding demonstrates the utility of microwave-assisted synthesis and provides a promising method for the preparation of silver nanorods.

Microwave-assisted Synthesis of Near-infrared-luminescent Ovalbumin-protected Gold Nanoparticles as a Luminescent Glucose Sensor

2014 ◽  
Vol 43 (6) ◽  
pp. 793-795 ◽  
Author(s):  
Junya Yoshimoto ◽  
Naoki Tanaka ◽  
Mitsuru Inada ◽  
Ryuichi Arakawa ◽  
Hideya Kawasaki
Keyword(s):  
Gold Nanoparticles ◽  
Near Infrared ◽  
Glucose Sensor ◽  
Microwave Assisted Synthesis ◽  
Microwave Assisted

scholarly journals Highly Sensitive and Selective Colorimetric Detection of Methylmercury Based on DNA Functionalized Gold Nanoparticles

Sensors ◽  
2018 ◽  
Vol 18 (8) ◽  
pp. 2679 ◽  
Author(s):  
Zheng-Jun Xie ◽  
Xian-Yu Bao ◽  
Chi-Fang Peng
Keyword(s):  
Gold Nanoparticles ◽  
Catalytic Activity ◽  
Limit Of Detection ◽  
Low Cost ◽  
Colorimetric Detection ◽  
Colorimetric Method ◽  
Optimal Conditions ◽  
Surface Deposition ◽  
Highly Sensitive ◽  
Dna Strand

A new colorimetric detection of methylmercury (CH3Hg+) was developed, which was based on the surface deposition of Hg enhancing the catalytic activity of gold nanoparticles (AuNPs). The AuNPs were functionalized with a specific DNA strand (HT7) recognizing CH3Hg+, which was used to capture and separate CH3Hg+ by centrifugation. It was found that the CH3Hg+ reduction resulted in the deposition of Hg onto the surface of AuNPs. As a result, the catalytic activity of the AuNPs toward the chromogenic reaction of 3,3,5,5-tetramethylbenzidine (TMB)-H2O2 was remarkably enhanced. Under optimal conditions, a limit of detection of 5.0 nM was obtained for CH3Hg+ with a linear range of 10–200 nM. We demonstrated that the colorimetric method was fairly simple with a low cost and can be conveniently applied to CH3Hg+ detection in environmental samples.

scholarly journals Synthesis and Characterization of YAG Nanoparticles by Ultrasound-Assisted and Ultrasound-Microwave-Assisted Alkoxide Hydrolysis Precipitation Methods

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Wei Si ◽  
Chao Ding ◽  
Siqi Ding
Keyword(s):  
Calcination Temperature ◽  
Yttrium Aluminum Garnet ◽  
Ph Value ◽  
Atomic Diffusion ◽  
Microwave Assisted Synthesis ◽  
Microwave Assisted ◽  
Intermediate Phases ◽  
Transmission Electron ◽  
Ft Ir ◽  
Ultrasound Assisted

Yttrium aluminum garnet (YAG, Y3Al5O12) nanoparticles were synthesized by ultrasound-assisted and ultrasound-microwave-assisted alkoxide hydrolysis precipitation methods. The effect of reaction parameters including pH value, ultrasonic radiation time, and calcination temperature on the composition of the products was investigated. The YAG nanoparticles and their precursor were characterized by X-ray powder diffraction (XRD), differential thermal analysis (DTA), Fourier-transform infrared spectroscopy (FT-IR), and high-resolution transmission electron microscopy (HRTEM). The results show that the single ultrasound-assisted method to synthesize YAG phase often contains intermediate phases of YAM (Y4Al2O9) and YAP (YAlO3); pure YAG phase can form only at special conditions and as single crystal. The pure phase YAG powders can be obtained at each experimental condition when using ultrasound-microwave-assisted synthesis and the grain is polycrystalline. This is due to the microwave radiation which promotes atomic diffusion and forms a lot of crystal nuclei of YAG in the precursor. The YAG nanoparticles with a grain size of 18 nm can be obtained at a calcination temperature of 900°C when using ultrasound-microwave-assisted method.

Sign in / Sign up

Export Citation Format

Share Document