Gamry FlexCell, Operator'S Manual

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Chapter 4: Routine Use of the Flexcell--Electrode Connections
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Electrode Connections
If you are using your Flexcell with a Gamry Instruments, Inc. potentiostat, make the following connections to
the electrodes:
1. Plug the reference-electrode lead into the white pin jack on the cell cable.
2. Attach both the green and blue leads from the cell cable to the working electrode (the metal
specimen).
• If you are using a thick specimen without the sample support, clip the alligator clip on each of these
leads to the threaded portion of the thumbscrew.
• If you are using a thin specimen with the sample support, clip these leads directly to the metal. If
you have bent one corner of the sample, clip to the bent area.
Some potentiostats may not have a blue cell lead. In this case, simply connect the green lead to the
working electrode.
3. Clip the red lead on the cell cable to the counter electrode.
4. Make sure that the floating ground (the longer black lead on the cell cable) cannot touch any other cell
connection. You may find that connection of this lead to a source of earth ground, such as a water
pipe, reduces noise in your experimental results.
5. If you are measuring very small currents, a metal enclosure completely surrounding your cell may
further reduce noise. In this case, connect this shield, known as a Faraday shield, to both ground leads
(short and long black leads) in the cell cable.
If you use the Flexcell with a potentiostat sold by a different manufacturer, consult that potentiostat ’ s
documentation for electrode connection information.
Controlling the De-ionized Water-flow Rate
For gravity feed using the intravenous set, you control the flow rate using the control valve that came with the
set. You can measure the flow with the drop counter. Each drop in the drop counter corresponds to 0.1 mL.
Set the flow rate with the cell filled with electrolyte and with a metal sample in place. Both the pressure from
the height of fluid and the tightness of the sample mounting affect the flow rate.
We recommend that you start with a flow rate of 6 mL/hour or one drop per minute. On one system that we
studied, varying the flow rate by a factor of two from this setting had no serious consequences. However, test
systems vary. The optimal flow rate for your particular chemistry could be quite a bit different.
Always double-check your cell connections. Even an experienced experimenter occasionally
leaves one of the cell-cable leads lying on the lab bench.
Caution:
The stirring rod is easily broken. Take care if you must remove the dome with the
rod in place.