Testing Reference Electrode Potential

  

Testing Reference Electrode Potential.

The simplest way to test an unknown reference electrode is to compare its potential with a known good reference electrode. Place the known good and unknown electrodes in a beaker containing an electrolyte. Momentarily connect the two electrodes to the inputs of a good quality voltmeter. Ideally the voltmeter’s input impedance should be 100 MW or greater. Try not to leave the voltmeter connected for a long period of time.

If the voltmeter reads less than 3 mV difference between the electrodes, the unknown reference is good enough for routine lab use.

If you do not have a known good reference electrode, get four or five electrodes of the same type. Check each electrode’s potential versus one electrode chosen as the "standard". Good electrodes should all have the same potential versus the standard. Any electrode different from the rest is probably bad.

If you do not have a high quality voltmeter, you can use your potentiostat to make the voltage measurement. Connect one reference electrode to the working electrode terminal of your potentiostat. Hook up the working sense wire if you have one. Connect the second reference in the normal fashion. Do not connect the counter electrode to anything and do not turn the cell on.

Immerse the reference electrodes in electrolyte. Read the open circuit voltage of the system. This is a measure of the potential difference between the two reference electrodes.

In a Gamry Instruments’ system, you can do this test using the Eoc vs. Time experiment, or by running any experiment and using its Initial Delay step.

  

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Last revised on Thursday, August 30, 2007