Hello Sir,

you got some real problem ( lot of work to lose, no honors to gain) but I am optimistic. Questions:

1. Which material is to be removed "after the experiment" (most important).

2.What is the exact geometry of the electrode tip including the EVA coat?

Not knowing the details, I have the following idea:

Some little atmospheric argon/hydrogen plasma jet should do it, specifically the "KinPen" by the INP at Greifswald, Germany. The system is commercially available from the company "Neoplas". It will remove most contaminants with little colateral damage. But still, there will be decomposition of the EVA if not properly masked. I recommend some mask from 2 metal pieces with the electrode fitting in between. Ask for Dr. Jan Schäfer who is a very good expert and fitted with the proper mind-set/fighting spirit.

Best wishes,

Heinrich

Heinrich Gruenwald Hello mister, thank you for your reply. I've read it earlier, but I've had to ask my colleagues for some feedback to answer your questions properly. My apologies for the delayed response.

1. This one I had to ask my colleagues for since they're working with those UMEs in experiments (I was only asked to fabricate them). UMEs are used for voltammetric measurements of organic metalloporphyrin-based monolayers grown on the surface of an pH-neutral aqueous electrolyte. So I presume the biggest issue will be to get rid of the remnants of those metaloporhpyrines.

Also when I do the checking of the UMEs, I study their CV anodic response in aqueous solution of 1mM potassium ferrocyanide with 100mM sodium sulfate. However, there should not be any problem with that in my opinion - all the compounds used or generated during the CV check are water soluble, therefore washing the electrodes with copius amount of distilled water should do the thing. But feel free to correct me if I am wrong in that assumption.

2. Well, the coating on the tip end resembles the half of an oval capsule (prolate spheroid), with PtIr wire located in the main axis. The etched tip of the wire (or the very apex of it, to be more specific) protrudes out at the vertex of the spheroid. Sometimes (depends on the shape of the etched tip) the coating deforms into the slight cone in the vicinity of the apex. Nevertheless the active surface area profile is expected to be conical/hemispherical (again, depends on the shape of the etched tip). Hope my English is good enough for sufficient description :)

Dear colleague, thanks for your efforts.

Still I believe that an Ar/H2 plasma can help you after you have removed the residues of the metaloporphyrine by careful rinsing and subequent soaking or blowing.

The hydrogen component of the plasma will transform any hydrocarbons into volatile stuff that will be taken away by the gas stream. So, the complexing agent will drop the metal. If the respective metal is forming a volatile hydride, it also will be removed from the surface.

Also, I still believe that Dr. Jan Schäfer at the INP at Greifswald is a most competent person to help you with his experience on fine plasma jets. Your English is more than fine and he may even understand Czechian language. Tell him best regards from me, please.

Good luck from

Heinrich