User:Hannah Harvey/Notebook/CHEM-471 Fall 2016/2017/02/21

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Changing Ratios


We changed the ratio of gold to protein by decreasing the concentration of protein to see if this allowed more gold to be oxidized and reduced. In addition, the current max and min differences between electrodes that had had different volumes of NPs absorbed on them was studied.


Figure 1. Graph of maximum current (A) vs. volume dried on GCE (mL)

Figure 2. Graph of minimum current (A) vs. volume dried on GCE (mL)


  1. Changing the volume of gold NPs placed on the electrode did not change the amount of current.


  • To compare current results for an increased myoglobin concentration (myoglobin:gold=65:1)


Electrochemical Analysis

  • CH Instruments Electrochemical Analyzer was used.
  1. 5 mM hexaammineruthenium(III) chloride and 1M KCl solution was used in electrochemical cell.
  2. The glassy carbon electrode was cleaned with 0.3 and then 0.05 alumina slurry and then sonicated.
  3. The reference electrode, the platinum wire, and the GCE were attached to the instrument.
  4. N2 gas was bubbled through the cell to eliminated the oxygen in the cell.
  5. The parameters were set at:
  • Initial: 0.2
  • High: 0.2
  • Low: -0.4
  • Initial Scan: Negative
  • Scan Rate: 0.05
  • Segments: 4
  • Sensitivity 1x10^(-5)
  • Sample Interval: 0.001
  1. Then the instrument was ran.
  2. This same procedure was with the addition of 20μL or 25μL of nanofibers which had been dropped onto the GCE and allowed to dry.
  3. The nanofibers had been centrifued at 1300rpm for 1 minute.


  • 1M KCl; 6μL nano; myo:gold=65:1

Figure 1 dV=.072V dC=9.72*10-5A

  • 1M KCl; 10μL nano; myo:gold=65:1

Figure 2 dV=.089V dC=8.20*10-5A

  • 1M KCl; 15μL nano; myo:gold=65:1

Figure 3 dV=.075V dC=9.47*10-5A

  • 1M KCl; 20μL nano; myo:gold=65:1

Figure 3 dV=.080V dC=8.87*10-5A


The 65:1 concentration nanofibers were determined to not be as effective as the 55:1 concentration nanofibers. We determined that the gold concentration was what needed to increase, not the myoglobin.


Cassidy Hart