# User:Melissa Novy/Notebook/CHEM-571/2012/09/04

< User:Melissa Novy‎ | Notebook‎ | CHEM-571‎ | 2012‎ | 09

<!-- sibboleth --><div id="lncal1" style="border:0px;"><div style="display:none;" id="id">lncal1</div><div style="display:none;" id="dtext">09/19/2012</div><div style="display:none;" id="page">User:Melissa Novy/Notebook/CHEM-571/2012/09/04</div><div style="display:none;" id="fmt">yyyy/MM/dd</div><div style="display:none;" id="css">OWWNB</div><div style="display:none;" id="month"></div><div style="display:none;" id="year"></div><div style="display:none;" id="readonly">Y</div></div>

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## Objectives

• Analyze AuNP/BSA solutions with UV-vis spectroscopy. Data will be posted next week.
• Make Tris buffer solutions at pH values of 8 and 10.
• Refer to Dhea Patel's entry for AuNP/BSA solution ratios, calculations, and images.

## Tris Buffer Solutions

• 100 mL of 0.1 M Tris buffer solution requires:
```  MW Tris: 121.14 g/mol
(0.1 mol Tris/1 L) × (121.14 g Tris/1 mol Tris) = 12.114 g Tris/L
(12.114 g Tris/1 L) × 0.1 L = 1.2114 g Tris/0.1 L
Theoretical mass of Tris: 1.2114 g
```
• 1.2114 g of Tris buffer was added to 100 mL of H2O to make a 0.1 M Tris buffer solution.
• While stirring to ensure even distribution of particles, the pH of the solution was adjusted to 8.0 with drops of 1 M HCl. The total volume of HCl used was about 7 mL.
• Another 100 mL of 0.1 M Tris buffer solution was made and its pH was adjusted to 10.0 with drops of 1 M HCl. The total volume of HCl used was about 1 mL.

## Absorbance Data

• Absorbance of AuNP/BSA solutions at concentrations ranging from 60 μM to 170 μM to determine the formation of AuNPs.
• A peak at around 530 nm for the 80 μM solution indicates the presence of AuNPs in solution. A visual confirmation was that the solution was also transparent purple in color.
• No peaks occurred for the other solutions, because no AuNPs formed. These solutions contained yellow-brown precipitate instead. The gold likely did not react with the BSA in the manner intended.

## Notes

• The original AuNP solutions did not form nanoparticles, as the HAuCl4 reacted with the metal spatula. They were yellow in color and the higher ratio solutions contained brown precipitate.
• Visual analysis indicated that all but the 60 and 80 Au/BSA solutions of the second set of AuNP+BSA solutions contained fibers.
• Please refer to Keyun Wang's entry for more observations about the solutions.