User:Sarah Burkhard/Notebook/471 Nano Notebook/2017/02/28

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  • prepare pH 8 - 13 amino acid solutions and put them in the oven (18 solutions total)
  • analyze data from last week's UV Vis

Preparation of solutions

Example Arginine, pH 8 . All other volumes and concentrations are found in our spreadsheet.

V final 5000 uL

V initial Gold 500 uL

V initial AA 313.9417532 uL

V water 3,685.06 uL

V pH adjuster 501.00 uL 5 mM NaOH

M initial Gold 5 mmolar

M initial AA 49.77037887 mmol changes w/ AA

M final Gold 0.5 mM

M final AA 3.125 mmolar


  • prepared new 5 mM NaOH solution with pH 11.74. This gives us an effective NaOH concentration of 5 mM.
  • we used 5 mM to adjust pH 8 - 11
  • we used 1 M to adjust pH 12 and 13
  • we sonicated the Cys precipitate before putting the solutions in the oven at 80 degrees for 4 hours


The order in which we add the solutions together seems to play a role. Upon adding gold and amino acids together, we observe immediate fiber / polymer formations for cysteine. Upon adding NaOH and water, the polymer seems soluble in pH 8, but precipitates at pH above 8. All other solutions remain clear.

Upon adding NaOH to the clear Gln-Gold mixture (to get to pH 12 and 13) the solution turns dark yellow for a split second. The strong yellow then fades to a weaker yellow.

The Cys precipitate dissipates at pH 12 and 13.