User:Elizabeth Ghias/Notebook/Experimental Biological Chemistry/2012/03/21

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To redo Fluorescence and UV-Vis Spectra, because the results obtained on 3/20 and 2/22 were not consistent. Spectra will be taken both after centrifugation and after pH changes.


  1. The three dye solutions from the second dye attachment trial were centrifuged for five minutes at 13200 rpm.
  2. The fluorescence spectra were then taken for all three solutions with excitation at 600nm and emission between 620 and 800 nm.
  3. The pHs of the three solutions were then measured. The 166 ratio solution with dye had a pH of 8.13. The 70 ratio solution with dye had a pH of 7.62. The BSA/HCl solution with dye had an initial pH of 7.75.
  4. The pHs of the BSA/HCl and the 70 molar ratio solutions were raised by adding 50 mM Tris buffer. The new pH of the 70 molar ratio solution with dye was 8.07, while the new pH of the BSA/HCl solution with dye was 8.09.
  5. The three solutions were then centrifuged again at 13200 rpm for 5 minutes.
  6. Fluorescence spectra were taken for all three solutions with dye.


Fluorescence Spectra After Centrifugation

21mar - fluorescence curve same sol.jpg

Fluorescence Spectra After Changing the pH

21mar - fluorescence curve ph changedl.jpg

UV-Vis Spectra After Changing the pH

21mar - UV curve ph changed.jpg

21mar - UV curve ph changed zoom.jpg


  • The results obtained today reproduced the results obtained the previous day (3/20).
  • Because the results did not match those that were obtained on 2/22, the pHs of those dye solutions (from the first trial) will be changed to match the pHs of the dye solutions from the second trial and the spectra will be redone.
  • The differences in the spectra are likely a result of the pH dependence of the dye.