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|style="background-color: #EEE"|[[Image:BDLlogo_notext_lr.png|128px]]<span style="font-size:22px;"> Biomaterials Design Lab</span>
|style="background-color: #EEE"|[[Image:BDLlogo_notext_lr.png|128px]]<span style="font-size:22px;"> Synthesizing Gold Nanoparticles</span>
|style="background-color: #F2F2F2" align="center"|<html><img src="/images/9/94/Report.png" border="0" /></html> [[{{#sub:{{FULLPAGENAME}}|0|-11}}|Main project page]]<br />{{#if:{{#lnpreventry:{{FULLPAGENAME}}}}|<html><img src="/images/c/c3/Resultset_previous.png" border="0" /></html>[[{{#lnpreventry:{{FULLPAGENAME}}}}{{!}}Previous entry]]<html>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</html>}}{{#if:{{#lnnextentry:{{FULLPAGENAME}}}}|[[{{#lnnextentry:{{FULLPAGENAME}}}}{{!}}Next entry]]<html><img src="/images/5/5c/Resultset_next.png" border="0" /></html>}}
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==Entry Title==
Synthesizing Gold Nanoparticles


==Objective==
==Objective==


To determine how pH affects the synthesis of gold nanoparticles (Au NP) using the procedure developed here:  
To determine how pH affects the synthesis of gold nanoparticles (AuNP) using the procedure developed here:  




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# Combine 10 mL of 50 mM acetate buffer (pH 5.46) with 1.1×10<sup>-3</sup> g of .0015 mM bovine serum albumin (BSA) and 4.0×10<sup>-4</sup> g of 0.25 mM chloroauric acid (HAuCl<sub>4</sub>) in a capped test tube at room temperature.
# Combine 10 mL of 50 mM acetate buffer (pH 5.46) with 1.1×10<sup>-3</sup> g of .0015 mM bovine serum albumin (BSA) and 4.0×10<sup>-4</sup> g of 0.25 mM chloroauric acid (HAuCl<sub>4</sub>) in a capped test tube at room temperature.
# Use a small amount of distilled water to aid in transferring measured quantities to capped test tube.
# Use a small amount of distilled water to aid in transferring measured quantities to capped test tube.
# Take UV vis spectra (200 nm to 800 nm) of buffer and reaction mixture.
# Take UV-vis spectra (200 nm to 800 nm) at room temperature of a sample of buffer and reaction mixture.
# Place reaction mixture in an oven at 80°C for 6 hr under thermostatic conditions.
# Place reaction mixture in an oven at 80°C for 2.5 hr under thermostatic conditions.
# Continue to take UV vis spectra of reaction mixture every 30 minutes.
# Continue to take UV-vis spectra of reaction mixture at room temperature every 30 minutes.
# After 2.5 hr, remove from oven and cool to room temperature; leave sitting overnight.
# After 2.5 hr, remove from oven and cool to room temperature; leave sitting overnight.


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'''Results:'''
'''Results:'''


The absorbance values for the acetate buffer were subtracted from absorbance values for the reaction mixture recorded by the UV-Vis to find a corrected absorbance value that would indicate the absorbance of the Au NP and the BSA only.
The absorbance values for the acetate buffer were subtracted from absorbance values for the reaction mixture recorded by the UV-vis to find a corrected absorbance value that would indicate the absorbance of the AuNP and the BSA only.


The corrected absorbance values at 550 nm (The wavelength that Au NP should absorb) were graphed against time. The graph (below) shows that some Au NP were created, as absorbance values do increase. However, it is possible some were destroyed as the absorbance rates do drop slightly starting at 120 min into the procedure.
The corrected absorbance values at 550 nm (The wavelength that Au NP should absorb) were graphed against time. The graph (below) shows that some AuNP were created, as absorbance values do increase. However, it is possible some were destroyed as the absorbance rates do drop slightly starting at 120 min into the procedure.




<center>[[Image:Absorbance vs time.jpg|600px]]</center>
<center>[[Image:Absorbance vs time 8-31-11.jpg|600px]]</center>




In addition, a second graph showing corrected absorbance against wavelength was created, to shed light on which time the Au NP began to form.  
In addition, a second graph showing corrected absorbance against wavelength was created, to shed light on which time the AuNP began to form.  




<center>[[Image:Absorbance vs wavelength.jpg|600px]]</center>
<center>[[Image:Absorbance vs wavelength 8-31-11.jpg|600px]]</center>




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<center>[[Image:Absorbance vs wavelength magnefied.jpg|600px]]</center>
<center>[[Image:Absorbance vs wavelength magnified 8-31-11.jpg|600px]]</center>


==Notes==
==Notes==
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[[Category:Course]]
[[Category:Course]]
[[Category:Miscellaneous]]
[[Category:Miscellaneous]]





Revision as of 09:49, 19 October 2011

Synthesizing Gold Nanoparticles <html><img src="/images/9/94/Report.png" border="0" /></html> Main project page
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Objective

To determine how pH affects the synthesis of gold nanoparticles (AuNP) using the procedure developed here:


Bakshi, Mandeep S.; Kaur, Harpreet; Khullar, Poonam, Banipal, Tarlok, S.; Kaur, Gurinder; Singh, Narpinder Journal of Physical Chemistry C 2011, 115(7), 2982-2992

http://pubs.acs.org/doi/abs/10.1021/jp110296y

Description

  1. Combine 10 mL of 50 mM acetate buffer (pH 5.46) with 1.1×10-3 g of .0015 mM bovine serum albumin (BSA) and 4.0×10-4 g of 0.25 mM chloroauric acid (HAuCl4) in a capped test tube at room temperature.
  2. Use a small amount of distilled water to aid in transferring measured quantities to capped test tube.
  3. Take UV-vis spectra (200 nm to 800 nm) at room temperature of a sample of buffer and reaction mixture.
  4. Place reaction mixture in an oven at 80°C for 2.5 hr under thermostatic conditions.
  5. Continue to take UV-vis spectra of reaction mixture at room temperature every 30 minutes.
  6. After 2.5 hr, remove from oven and cool to room temperature; leave sitting overnight.

Data

Calculations:

  • Determining the mass of HAuCl4 needed for a concentration of 0.25 mmol/L in 10 mL of acetate buffer solution.
0.25 mmol/L HAuCl4 × (1 mol/1000 mmol) = 2.5×10-4 mol/L HAuCl4
10 mL solution × (1 L/1000mL) × (2.5×10-4 mol HAuCl4/1 L) × (196.967 g Au3+/1 mol) = 4.9×10-4 g AuCl4
  • Determining the mass of BSA needed for a concentration of 0.0015 mmol/L in 10 mL of acetate buffer solution.
0.0015 mmol/L BSA × (1 mol/1000 mmol) = 1.5×10-6 mol/L BSA
10 mL solution × (1 L/1000 mL) × (1.5×10-6 mol BSA/1 L) × (66776 g BSA/1 mol) = .0010 g BSA


Results:

The absorbance values for the acetate buffer were subtracted from absorbance values for the reaction mixture recorded by the UV-vis to find a corrected absorbance value that would indicate the absorbance of the AuNP and the BSA only.

The corrected absorbance values at 550 nm (The wavelength that Au NP should absorb) were graphed against time. The graph (below) shows that some AuNP were created, as absorbance values do increase. However, it is possible some were destroyed as the absorbance rates do drop slightly starting at 120 min into the procedure.



In addition, a second graph showing corrected absorbance against wavelength was created, to shed light on which time the AuNP began to form.



Another version of this graph, showing the absorbance from 0 to 0.5 was also created to better illustrate the changes at 550 nm. It appears the changes are due to a change in the baseline reading, rather than an increase due to nanoparticle production.


Notes

The reaction mixture remained clear for most of the experiment, until towards the end when a slight yellowish tinge appeared. Bashki, et al indicated that the mixture should be purplish in color. This could indicate that the reaction did not occur properly and may need to be repeated.