I want to measure pre polarization potentiostatic (for different times), So can i use same working electrode for different measurements while not changing my solution and working electrode, or should I change my electrode for every new measurements to be more precise.
WE is titanium and solution is aqueous Nacl
Thanks
It depends on the target of your experiment and the sign of polarization. However, when the mass Mp of precipitates is high (say Mp/Me>>1% : mass Me of the electrolyte) then it is better to renew, at least, the electrolyte.
Say, if you want collaboration. I studied these systems 10y (unpublished), ago.
As Ioannis said: it depends. Generally if you are poising the electrode either at open circuit or negative of open circuit you can continue to use the same sample. Also, even if you are polarizing the sample (EIS, LPR) so long as you are staying within 20 mV of the open circuit the test is considered "non-destructive" and the same sample can be used repeatedly (this is how experiments like RPEC trend and EFM trend work). That said, in some cases this doesn't tend to hold up. e.g. Al does not do well with potentials negative of OCP, and smaller volume cells may have relevant concentration changes, even if the net current = 0. I'm not particularly familiar with TI, but It sounds like Ioannis is.
I agree with Jacob and Ioannis. The Ti electrodes are normally innert but the "contamination" of the interface electrode//electrolyte could change intrinsically the behaviour of the electrode in subsequent electrochemical tests, especially if you are looking for the absolute values in such measurements. Whether this is a case you can check the pre-polarized electrode by measuring the rest potential of it in the same parent testing solution and compare the rest potential values of Ti electrodes before and after pre-polarization. If the potential differences are not higher than +/- 3 mV (keep in mind the constant RT conditions) it should be no problem in reusing the Ti electrode in subsequent testing.
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