1. Electrode Array GK-12 Meeting November 2nd 2010
Megan Easterly

2. Electrochemistry Oxidation Reduction Loss of electrons
Electrode removes electrons from the solution
Anodic peak current
Reduction
Gain of electrons
Electrode gives electrons to the solution
Cathodic peak current

3. Electrodes Working (WE) Reference (RE) Auxillary (AE) Electrolyte
Where the reaction of interest occurs
Current is measured
Reference (RE)
Measures WE potential by maintaining a stable potential
Auxillary (AE)
Electron provider/remover
Electrolyte
Electrically conductive solution

4. Gold Electrode Array 8 Au working 1 Au reference 1 Au auxillary2 3 4 5 6 7 8
aux
ref
8 Au working
1 Au reference
1 Au auxillary
Study FDCA

5. Ferrocenedicarboxylic Acid (FDCA)
E0 ferrocene = V vs. NHE
0.197 MORE positive
Bard, A.; Faulkner, L., “Electrochemical Methods. Fundamentals and Applications” 2nd Ed. Wiley, New York. 2001
Image courtesy of Dr. Karst research group:

6. The Math Randles-Sevcik equation
is a collection of constants at 25 oC
0.443 * Fardays constant * universal gas constant
Should be linear under a diffusion controlled case
Bard, A.; Faulkner, L., “Electrochemical Methods. Fundamentals and Applications” 2nd Ed. Wiley, New York. 2001

7. Simultaneous Detection
External reference and auxillary

8. Simultaneous Detection
Normalized currents to electrode area
Linearity
>
Sensitivity (μA*mm-2*mM-1)
Ox 1.43 ± 0.07
Red ± 0.07

9. DPV of FDCA Optimal potential determination Ran individually
vs. AgAgCl
0.43 V
vs. Au
0.37 V
Ran individually

10. Amperometry of FDCA On-chip reference and auxillary
0.37 V
Individual detection

11. Amperometry of FDCA Normalized to electrode area Linearity Sensitivity
>
Sensitivity
22.44 ± 12.93
nA*mm-2*mM-1

12. New Mask Well defined areas Working = 0.09 mm2 Reference = 2.25 mm2
Auxillary = 2.25 mm2
Spacing = 0.3 mm

13. Future Work Fabrication of new electrode array
Chemiluminescence detection of NO donor
Calibration of electrodes using NO
Modification of Au array
Nafion
Polypyrrole
Diab, N.; Oni, J.; Schulte, A.; Radtke, I.; Blochl, A.; Schuhmann, W., Talanta, 61, 2003, 43-51