We are using GCE for Electrochemical sensing purpose. We dropcasted Graphene on the electrode surface and tried to observe the redox peaks in potassium ferricyanide solution. We got the proper redox peak for the first time, further on polishing with Alumina slurry no redox peaks were observed in potassium ferricyanide even in bare GCE. So what would be the possible problems and the solution?
You did rightly. Can you try to polish the surface with emery paper (not very coarse) with fine particle. You may polish the surface by changing the place followed by sonication every time. Then you may do the rest what you have done before.
Best of luck.
MMI
You did rightly. Can you try to polish the surface with emery paper (not very coarse) with fine particle. You may polish the surface by changing the place followed by sonication every time. Then you may do the rest what you have done before.
Best of luck.
MMI
Look at the current after polishing, it turns into nA from uA. So there are few probable reasons behind this:
1. electrical connection loss due to sonication (GCE should not sonicate for longer time)
2. Alumina slurry (non conducting) is sticked on the surface.
Try to apply high potential of e.g. 1.8V vs. SCE for a certain time (may be few minutes).
or follow the procedure described in detail in this file:
http://www.asdlib.org/onlineArticles/elabware/kuwanaEC_lab/PDF-27-Care&Feeding.pdf
best,
It seems that you are employed all the three possibilities: mechanical, chemical or electrochemical. I don't know the solution in your specific case, because I don't know how was graphene added and if the problem is that you have noise or no signal at all. The polishing with alumina is critical and alumina particles have to be totally removed for avoiding noise. Check also the reference electrode.
You say in the figure "coating and polishing". The opposite should be made. It seems, from the slope in the CV that there are too much resistence. Increase the conductivity and try to decrease distance in between electrodes.
It seems that you have very high resistance as your curve is completely Tends
Can you tell me what is the kind of your GCE, is homemade or you get a ready made one? and its design?
Because this problem of high resistance comes mainly from the leakage, which allow your electrolyte during measurements (or solution during ultrasonication), to go between GC and the metallic contact you use.
So, you have to remove this solution and you will restore your electrode
Thank you all.
Kind attn to Alaa A. El-Shafei
GCE is not a home made. Readymade one, bought from USA based company. And the specification is 6 cm length, 3 mm dia of active surface area, and 6mm overall diameter.
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