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Cyclic voltammogram in 3-electrode mode using an EPC 10 USB patch clamp amplifier
Most suitable for this measurement is an EPC 10 USB Double patch clamp amplifier.
With the 3-electrode headstage the EPC 10 USB can measure the potential difference
between a third electrode (reference) and the ground (counter) electrode without
having current flowing through the reference electrode. The reference electrode
stays in equilibrium! The potential difference is added to the command potential
for the working electrode.
With the 3-electrode mode headstage the EPC 10 USB patch clamp amplifier has the
performance of a high-end potentiostat/galvanostat with a scan range of +/- 1V.
Measuring Configuration
Working electrode:
Platinum microdisk electrode with 10 µm electroactive diameter.
Reference electrode:
Ag/AgCl electrode
Counter (GND) electrode:
Platinum
Redox mediator (bath solution):
0.7 mM FcMeOH dissolved in 0.117 M KCl
Cyclic Voltammogram
We have scanned the potential of the working electrode with respect
to the reference electrode from 0 mV to 400 mV, then to –200 mV and
back to 0 mV with a scan rate of 100 mV/s and recorded the current at
the working electrode with a bandwidth of 3 kHz.
Analysis of the CV
The diffusion limiting current is determined as 1.2 nA which describes
a microdisc electrode with 10 µm electroactive diameter at a concentration of
0.7 mM. The polarographic half wave potential is detected as +150 mV vs. Ag/AgCl.
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