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

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Objectives

  • Analyze AuNP+BSA solutions with UV-vis spectroscopy.
  • Remake AuNP+BSA solutions that did not produce the expected peaks on their UV-vis spectra.
  • Make Tris buffer solutions at pH values of 8 and 10.
  • Refer to Dhea Patel's entry for UV-vis data.

Abigail E. Miller 09:45, 17 September 2012 (EDT) there is no indication in your notebook that you completed the second objective. what data exactly is available in Dhea's notebook? Absorbance measurements of what and why?

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

Image:9-4-12_Absorbance_AuNP-BSA.JPG

  • 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.



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