Effect of Citrate Concentration on Colloidal Gold (Au) Nanoparticles Produced Using Electro-Dissolution-Reduction Method

2016 ◽  
Vol 840 ◽  
pp. 267-270
Author(s):  
Haroon Haiza ◽  
Iskandar Yaacob ◽  
Ahmad Zahirani Ahmad Azhar
Keyword(s):  
Gold Nanoparticles ◽  
Electron Microscope ◽  
Colloidal Gold ◽  
Reduction Process ◽  
Chloride Ions ◽  
Complex Ions ◽  
Citrate Concentration ◽  
Dc Power ◽  
Colloidal Gold Nanoparticles ◽  
Transmission Electron

Colloidal gold nanoparticles have been successfully synthesized using electro-dissolution-reduction process that consists of a simple two-electrode cells connected to a DC power supply. Throughout the process, bulk gold at the anode was oxidized into gold cations which then reacted with the chloride ions to form aurochloride complex. The complex ions were then reduced by the citrate ion to form colloidal gold nanoparticles. The size and shape of the nanoparticles were modulated by varying the citrate concentration. The colloidal gold nanoparticles obtained were characterized by field-emission scanning electron microscope (FESEM), transmission electron microscope (TEM) and ultraviolet-visible spectrophotometer (UV-Vis). From FESEM analysis, it was found that by increasing the citrate concentration, the size of colloidal gold nanoparticles produced marginally increased. The mean sizes of gold nanoparticles were roughly about 18.7 nm, 19.3 nm, 20.5 nm and 21.3 nm for citrate concentrations of 0.05 M, 0.10 M, 0.15 M and 0.20 M, respectively. However, sample prepared without the addition of citrate, remained colorless indicating that aurochloride complex ions were not reduced to colloidal gold nanoparticles. TEM micrographs showed that the shape of gold nanoparticles obtained is almost spherical. The characteristic peaks of UV-Vis spectra revealed that the suspension was indeed colloidal gold nanoparticles.Keywords: Gold, Nanoparticles, Electro-dissolution-reduction

Effect of Voltage on Colloidal Gold (Au) Nanoparticles Produced Using Electro-Dissolution-Reduction Method

2015 ◽  
Vol 1115 ◽  
pp. 386-389
Author(s):  
Haroon Haiza ◽  
I.I. Yaacob ◽  
Ahmad Zahirani Ahmad Azhar
Keyword(s):  
Gold Nanoparticles ◽  
Electron Microscope ◽  
Colloidal Gold ◽  
Reduction Process ◽  
Chloride Ions ◽  
Complex Ions ◽  
Dc Power ◽  
Colloidal Gold Nanoparticles ◽  
Transmission Electron ◽  
The Mean

Colloidal gold nanoparticles have been successfully prepared using a simple two-electrode cells connected to a DC power supply. During the electro-dissolution-reduction process, the bulk gold at the anode oxidized into gold cations which then reacted with the chloride ions to form aurochloride complex. The complex ions were then reduced by the citrate ion to form colloidal gold nanoparticles. The size and shape of the nanoparticles were modulated by varying the terminal voltages. The colloidal gold nanoparticles obtained were characterized by field-emission scanning electron microscope (FESEM), transmission electron microscope (TEM) and ultraviolet-visible spectrophotometer (UV-Vis). From FESEM analysis, it was found that by increasing the voltage, the size of colloidal gold nanoparticles produced marginally decreased. The mean sizes of gold nanoparticles were roughly about 23.5 nm, 23.2 nm and 19.3 nm for 32 V, 36 V and 40 V, respectively. TEM micrograph showed that the shape of gold nanoparticles obtained is almost spherical. The characteristic peaks of UV-Vis spectra revealed that the suspension was indeed colloidal gold nanoparticles. Keywords: Gold, Nanoparticles, Electro-dissolution-reduction

Inter-band Transition in Citrate Capped Marks Dodecahedral Colloidal Gold Nanoparticles

2020 ◽  
Vol 16 (5) ◽  
pp. 829-836
Author(s):  
Debasish Aich ◽  
Pijus Kanti Samanta ◽  
Satyajit Saha ◽  
Tapanendu Kamilya
Keyword(s):  
Gold Nanoparticles ◽  
Fermi Level ◽  
Colloidal Gold ◽  
Interband Transition ◽  
Visible Absorption ◽  
Colloidal Gold Nanoparticles ◽  
Transmission Electron ◽  
Long Time ◽  
Band Transition ◽  
Absorbance Peak

Background: Optical properties of citrate capped dodecahedral gold nanoparticles have immense applications in a large variety of fields. The interband transition has a role in determining the optical behaviour of gold nanoparticles. Interband transition in citrate capped colloidal gold nanoparticles in the size range above ~5 nm has been left unattended for a long time. Objective: The present work is aimed at studying interband transition in citrate capped colloidal gold nanoparticles of size between ~5 nm and several tens of nanometres. Methods: Turkevich method and modified Brust method were used to prepare citrate capped colloidal gold nanoparticles. Transmission electron microscopy was used to determine their size and shape and their formation was explained with simulated figure obtained by Gnuplot programming. Interband transition was studied with the help of UV-Visible absorption spectroscopy. Results: Dodecahedral citrate capped colloidal gold nanoparticles of mean diameters 31.5 nm, 12.87 nm and 4.69 nm with LSPR peak positions at 528 nm, 524 nm and 509 nm were prepared. The interband peak of nanoparticles of all three sizes was found to be located at about 260 nm. Conclusion: Interband transition between Fermi level and 5d bands of the larger density of states in citrate capped dodecahedral colloidal gold nanoparticles of size above ~5nm leads to absorbance peak at ~260 nm, indicating a gap of ~4.77 eV between the Fermi level and closely spaced 5d bands. For smaller nanoparticles, absorption due to interband transition becomes more prominent relative to surface plasmon resonance absorption.

scholarly journals Study on synthesis of colloidal gold nanoparticles and preparation of antiE. coli O157 monoclonal antibody conjugated nanoparticles

2013 ◽  
Vol 16 (3) ◽  
pp. 75-82
Author(s):  
Thanh Vo Ke Ngo ◽  
Giang Dang Nguyen ◽  
Vinh Quang Lam ◽  
Dat Thanh Huynh
Keyword(s):  
Gold Nanoparticles ◽  
Colloidal Gold ◽  
Chemical Reduction ◽  
Major Effect ◽  
Chloroauric Acid ◽  
Visible Absorption ◽  
E Coli ◽  
Colloidal Gold Nanoparticles ◽  
Transmission Electron ◽  
20 Nm

The present paper describes the preparation of colloidal gold nanoparticles by a chemical reduction method, using some chemical compounds such as sodium citrate (Na3Ct), chloroauric acid (HAuCl4.3H2O) and anti-E. coli O157 monoclonal antibodyconjugated gold nanoparticles. The nanoparticles were characterized by several techniques including Ultraviolet and Visible Absorption Spectroscopy (UV-Vis), Transmission Electron Microscopy (TEM). The UV-Vis confirmed that the concentration of Na3Ct has a major effect on the size of the synthesized gold nanoparticles, and TEM images showed that the size of gold particles is in the range of 10-20 nm. In addition, the binding of the antibody-gold conjugates to E. coli O157 was also investigated using the same characterization means

Dense aqueous colloidal gold nanoparticles prepared from highly concentrated precursor solution

2011 ◽  
Vol 362 (2) ◽  
pp. 325-329 ◽  
Author(s):  
Tetsuro Soejima ◽  
Seisaku Oshiro ◽  
Yasuji Nakatsuji ◽  
Seishiro Ito
Keyword(s):  
Gold Nanoparticles ◽  
Colloidal Gold ◽  
Precursor Solution ◽  
Colloidal Gold Nanoparticles

An enhanced ELISA based on modified colloidal gold nanoparticles for the detection of Pb(II)

2011 ◽  
Vol 26 (8) ◽  
pp. 3700-3704 ◽  
Author(s):  
Yu Zhou ◽  
Xiang-Li Tian ◽  
Yan-Song Li ◽  
Feng-Guang Pan ◽  
Yuan-Yuan Zhang ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Colloidal Gold ◽  
Colloidal Gold Nanoparticles

scholarly journals Back Cover: Unconventional Chain-Growth Mode in the Assembly of Colloidal Gold Nanoparticles (Angew. Chem. Int. Ed. 32/2012)

2012 ◽  
Vol 51 (32) ◽  
pp. 8122-8122 ◽  
Author(s):  
Hong Wang ◽  
Liyong Chen ◽  
Xiaoshuang Shen ◽  
Liangfang Zhu ◽  
Jiating He ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Colloidal Gold ◽  
Growth Mode ◽  
Chain Growth ◽  
Back Cover ◽  
Colloidal Gold Nanoparticles
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