User:Mary Mendoza/Notebook/CHEM 571 Experimental Biological Chemistry I/2012/09/05

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Preparation of specific Au/BSA mole ratio solutions

  • Evaluating the peaks from the graph of the initial UV-Vis scan of Au/BSA solutions[[1]], it is evident that there are significant peaks ranging from mole ratios, 120, 128, 130, 132, 133, and 134. Hence, it was decided to prepare a set of new solution of the mentioned mole ratios to verify whether the drop between peaks are significant.
  • Using the prepared Au and BSA stock solutions from the previous lab, volumes needed for Au/BSA solutions were calculated.
  • The volume for BSA was held constant to 0.6 mL so as the total volume of the Au/BSA solution to 6 mL.
  • The same calculations were used for determining the volume needed for Au and water. [[2]]
  • After combining the three substances, Au, BSA, and water, into solution, the solutions were wrapped in foil and placed in the oven for 4h. at 85°C.
  • The initial appearance of the solutions were clear and colorless liquids.


HAuCl4/BSA ratio volume of Au (mL) volume of BSA (mL) H2O (mL)
120.1440.65.256
128.1530.65.247
130.1550.65.245
132.1580.65.242
133.1590.65.241
134.1600.65.240


Testing the effect of Tris Buffer pH 8

  • The Au/BSA solution made from August 29 was transferred to plastic centrifuge tubes.
  • The plastic centrifuge tubes which now contains the Au/BSA solutions were placed balanced inside the centrifuge chamber. The conditions were set to 3000 rpm at 10°C for 5 min.
  • When the centrifuge was over, the supernatant from the Au/BSA solutions were removed by pipet.
  • The tris buffer (pH 8) was added by serial dilution using micropipet. The ratio of the volume of tris buffer an water are listed on the table below.
  • The solutions were allowed to mix by venting. Three runs of UV-Vis scans were done for all solutions. The runs were scheduled in 1 h. intervals. 150 μL of the solution was taken using a micropipet. A single cork black cuvette was used for all runs.
  • The first run was scheduled at 2:30 PM followed by the second run at 3:30 PM.
  • The third run was scheduled for next meeting on September 11, 2012.
Test Tube volume of tris buffer pH 8 (mL) volume of water (mL) concentration of tris buffer (M)
1100.1
2191x10-2
3.19.91x10-3
4.019.991x10-4
5.0019.9991x10-5
6.00019.99991x10-6
7.000019.999991x10-7


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