User:Michael F. Nagle/Notebook/Chem 571/2012/09/04: Difference between revisions

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==Procedure==
==Procedure==
#UV/Vis
*UV/Vis
##On [[User:Michael_F._Nagle/Notebook/Chem_571/2012/08/29|8.29]], samples were made with varying mole concentration of HAuCl<sub>4</sub> and BSA. .1mL of each solution was inserted into a cuvette, which went into a UV/Vis Spectroscoper
**.1mL of each Au/BSA solution was inserted into a quartz cuvette, which went into a Shimadzu UV-2550 Spectrophotometer.
 
***These are not the same solutions prepared [[User:Michael_F._Nagle/Notebook/Chem_571/2012/08/29|8/29]], as the HAuCl<sub>4</sub> did not react, perhaps due to contamination from using a metal spatula that was not wrapped in parafilm. The solutions used here were prepared by [[User:Abigail_E._Miller|Dr. Miller]
##Cuvette was cleaned between each spectra, and the same cuvette was used each time
**Cuvette was cleaned between each spectra and the same cuvette was used each time
#Tris buffer serial dilution
*Tris buffer serial dilution
## Solutions with varying mole ratios of HAuCl<sub>4</sub> and BSA were centrifuged. The fibers became stuck along the side of the tubes and liquid was dumped.
** After being analyzed via UV/Vis, all HAuCl<sub>4</sub> and BSA solutions were centrifuged. The fibers became stuck along the side of the tubes and fluid was dumped.
## .1M solution of Tris was needed to begin serial dilutions.
** .1M solution of Tris was prepared at pH's of 8 and 10 by [[User:Puja_Mody/Notebook/Chem_571:_Gold_Nanoparticles/2012/09/04|Puja Mody]]
### .1M Tris * .1L = .01mol
** 9mL H<sub>2</sub>O was added to each tube. A serial dilution was completed using Tris buffer at pH of 8.
### .01mol Tris * 121.14g/1mol = 1.21g Tris
** 1mL Tris stock was added to the first tube. 1mL from this tube was moved to the next tube, and so on for the 12 remaining tubes with fibers.
### Stock solution of Tris was made at pH 8 and 10.
#### 1.21g Tris was added to each tube, with 85mL H<sub>2</sub>O
#### HCl was added dropwise until the pH changed to 8 and 10 in each tube, as indicated by a pH meter. 9mL HCl was added for pH=8 and 2mL was used for ph=10.
#### Sufficient water was added to leave the final volume of the solution at 100mL.
## 9mL H<sub>2</sub>O was put in the first tube to receive 1mL Tris from the stock solution.
## 1mL was taken from the tube with a pipette and moved to the next tube. 1mL from this tube was moved to the next tube, and so on until all get some amount of Tris.


==Data==
==Data==

Revision as of 19:22, 6 December 2012

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Objective

  • Using UV/Vis, find optimal mole ratio of HAuCl4 to BSA for nucleation of gold nanoparticles in solution.
  • Resuspend Au/BSA fibers with Tris buffer
    • Find optimal pH and concentration of Tris for resuspension

Procedure

  • UV/Vis
    • .1mL of each Au/BSA solution was inserted into a quartz cuvette, which went into a Shimadzu UV-2550 Spectrophotometer.
      • These are not the same solutions prepared 8/29, as the HAuCl4 did not react, perhaps due to contamination from using a metal spatula that was not wrapped in parafilm. The solutions used here were prepared by [[User:Abigail_E._Miller|Dr. Miller]
    • Cuvette was cleaned between each spectra and the same cuvette was used each time
  • Tris buffer serial dilution
    • After being analyzed via UV/Vis, all HAuCl4 and BSA solutions were centrifuged. The fibers became stuck along the side of the tubes and fluid was dumped.
    • .1M solution of Tris was prepared at pH's of 8 and 10 by Puja Mody
    • 9mL H2O was added to each tube. A serial dilution was completed using Tris buffer at pH of 8.
    • 1mL Tris stock was added to the first tube. 1mL from this tube was moved to the next tube, and so on for the 12 remaining tubes with fibers.

Data

File:BSA AuNP Uv-Vis.xlsx

Discussion

  • Concentrations of 128-134 should be retested because a significant drop in absorbancy was observed between these values and 120 and 138. Between the mole concentrations of 120 and 128, and 134-138, a significant change in peak height in seen. This indicates a difference in the amount of gold nanoparticles in solution. The range of 128-134 should be tested again because all other concentrations, higher and lower, have much higher peaks.
  • Dissolution of fibers in Tris should be tested at pH's 8 and 10 because Tris's optimal range is 7-9. Previous experiments used a pH of 10, which should also be tested so these can be replicated.


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