EEG (Electroencephalogram) is a technique for recording electrical activity of brain. Traditionally Ag/AgCl, Ag, Stainless Steel are used as the electrode material. Can copper be used for dry EEG electrodes ?
I am afraid copper would start to electrochemically interact with the skin (not really dry - especially after cleaning it from fat to lower the impedance) very soon (minutes) which would change the impedance of your setup or even introduce a potential like a battery (skin pH0). Ag/AgCl in combination with a NaCl gel remains very stable during the period of EEG measurement.
I agree with Frank Schmitz's answer above. However, if you determine that for other reasons you wish to or need to use copper, i would proceed and measure the electrode/skin contact impedance in a very meticulous method. For example, measuring impedance using a AC current source not just a DC current source, I'd also recommend close attention to matching impedances for any electrode pair input to differential amplifiers. You could also take these measurements before and after your procedures and take the differences into account in your data analysis. This step of electrode impedance measurements before and after procedures was routine practice in our lab procedures even with Ag/AgCl when i was actively engaged in the lab.
I agree with above. And I see no reason to use copper when there are perfectly acceptable electrodes already available. Including dry electrodes from companies like Neuroelectrics.
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