The reference electrod I use is saturated calomel electrode (3M KCl as the filling solution). I got overload problem while measuring the EIS, so then I checked the impedance of the electrod and the result showed that it is so high (10000 ohm) and not acceptable as it should be below 1000 ohm. As a solution, I changed the frit but the problem remain the same.
What could you suggest to solve this problem?
Thank you.
Dear Dr. İrem Cemre Türü,
only two further precautions about:
Bubbles and Reference Electrode Impedance
A reference electrode with a gas bubble interrupting its electrolyte path has a very high impedance. The bubble can be produced by electrolysis, from deaeration gas, outgassing of a heated electrolyte, or from trapped air. You should always check that your electrochemical setup has an unbroken electrolyte path from the working electrode to the sensing element within the reference electrode.
Be especially careful if you reference electrode has a flat isolation frit. If this flat surface is horizonal within the cell, it can easily trap a gas bubble. A 45 degree angle on this surface allows natural convection to remove any bubble that tries to stick on this surface.
For more details, please see the source at: https://electrochemistryresources.com/reference-electrodes/
Good luck and best regards, Pierluigi Traverso
Thank you very much Pierluigi Traverso .
I will consider your valuable advices. I will check the electrolyte path and the frit again.
Also thank you for the source.
Best regards.
As, Pierluigi Traverso.
Also, some adulterant plagues (pollution) might rise another/additional (Zamp) impedance issues, valid, mostly, in cases of old(er) REs; if a high(er) percentage of actual surface[1] contaminants is the main source of the high electrode's impedance (Zamp,RE >>1000 Ohm, or/and Zphase,RE >>5o deg., near/at 1 kHz) in old REs, then some additional cleaning, and/or recondition tips[2] might be helpful or even needed[3].
However, the exact cleaning process depends on the previous (historical laboratory-book) use, e.g. on the contaminants' timeline (REhistory).
1. e.g. any of the RE-interface(s).
2. How to Store, Clean, and Recondition pH Electrodes https://mrclab.com/data/products/CATALOG//PH%20Electrode%20Maintenance.pdf
3. With/Ask for the permission of your supervisor.
Thank you very much Ioannis Samaras . I will take into account the cleaning process.
Best regards.
May I add, that most importantly you have to use a Lugin-capillary to avoid any solution resistance caused by the separation distance between the RE and the WE, especially if the woking solution has high resistance.
Thank you Fakiha Heakal . I already use a Lugin-capillary in all experiments.
Best regards.
Thank you Qi Zeng ,
I have never tried calibrating the reference electrode. I will consider your advice.
Best regards.
It is better to use a saturated KCL solution
The tip pf luggin capillary tube must be adjacent to the working electrode to avoid the ohmic drop (IR) overpotential
Dera Abdelkader Dehbi, I strongly suggest that you stop copying other researchers' answers! 👎🏿
Please check carefully your reference electrode. The electrolyte in the outside tube should be free from any air bubbles, and covering 2/3 the inside tube containing the electrode costituents (Hg, Hg2Cl2, KCl(s)). If the electrolyte level is in a lower level, please complete the electrolyte using a syringe filled with 3 M KCl solution. Another quick check is to measure the potential difference between two similar reference electrodes, the potential shoul be equal zero volt, indicating that the two electrodes are OK. Good luck.
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