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Can I use an SPE more than once?

Yes, the electrodes can be reused for multiple runs or even a series of experiments. Users can typically get one to two class periods worth of data from one SPE. However, this depends heavily on the experiment. Acetaminophen is a very “sticky” chemical for the SPE, so the quality of CV will go down over time the more you use the same SPE with acetaminophen solutions. Ferricyanide or RuHex are not nearly as sticky and can last for dozens of runs without a deterioration in data. Electroplating onto the SPE can only be done once. 

The software does provide a way to reactivate the carbon surface of the electrode so you can reuse it again. Instructions for that can be found in the user manual.

SPE Diagram

Each electrode pattern contains a carbon working electrode (5 mm × 4 mm rectangle), a carbon counter electrode, and a silver/silver chloride reference electrode screen printed on a single substrate. These electrodes are screen printed on a polymer substrate and are for use in aqueous solutions only.

The screen printed electrodes come with 5 pads that connect to the GDX-CVS.  Only four of those pads are used, as shown in the figure. 

The GDX-CVS potentiostat controls and measures at the working electrode; therefore, there are two separate “leads” or “pads” on the screen-printed electrode that connect to the instrument separately, even though they are both connected to the same working electrode (labeled in red).

With the GDX-CVS, the working (current) pad and working (voltage) pad are always connected.  You can think of them as “2 contact pads to 1 electrode.”  Neither is a ground.

The reason they are separated is that these same SPEs are used with other instruments and experiments when it may be desirable to connect two leads to the working electrode.  For the GDX-CVS, this is inconsequential, they are always shorted together.

Related TILs
Go Direct Cyclic Voltammetry System Troubleshooting and FAQs
Can I get a platinum electrode for the Cyclic Voltammetry System?
The SPE doesn't fit straight in my GDX-CVS.