I am trying to perform cyclic voltammetry of a suspension of Carbon Black Particles (CB) in aqueous electrolyte solution. My goal is to make an analytical study of redox functional groups existing on CB particles surface (such quinones), using cyclic voltammetry.
There is some polarographic studies which use a Hanging Mercury Electrode (HMDE) but I do not have such a kind of WE. Does anyone know if I can perform electrochemistry of a suspension in a three-electrode-system using Glassy carbon as WE?
Yes Marius you can proceed with GC as working electrode. Three electrode system is much reliable than HMDE system. Potentiostat can be employed in your study to get various electrochemical analysis.
We always used glassy carbon for quinone-derivatives. It worked quite fine, though the kinetics might be a bit sluggish compared to other electrode/analyte systems.
This experiment would be little difficult, since the diffusion rate of the electrochemically active species are actually in the suspension sample. I would rather recomend to modify the surface of an electrode. Then use the modified electrode to perform the experiment in an electrolyte solution.
Diffusion of the suspension particles would be very likely too slow to give you a meaningful cyclic voltammogram (CV). If your purpose is to understand the redox properties of the surface groups on the particles, it is much easier to attach the particles onto the surface of your glassy carbon electrode. This can be achieved using the so called "cast-evaporate" method. In this way, you may need to add an inert polymeric binder (e.g. PTFE) to assist the adhesion of the particles to the electrode surface. Once you have made such a coated electrode, you can immerse it in the appropriate electrolyte to record CVs.
Try to use an ultrasonic horn to increase the rate of mass transfer at the electrode surface. you may also be able to obtain a significant current without an electrolyte.
Yes, I think you can use it. But you may have problems of adsorption on the electrode surface. I think you had to verify if you find the same behaviour with a Pt and maybe also Au electrodes.
check this http://www.mnf.uni-greifswald.de/fileadmin/Biochemie/AK_Scholz/Lehre/fritz/L61.pdf
In principle, any electrode including glasscarbon electrode can be used for the suspensions, However, the particles being larger in size compare to the molecular redox system, the slow diffusion will be limit the current due to the electro tranfe. So, in such situation the the particles are drop-casted on the the working electrode and the expriment can be performed in three electrode system.
The ability to use an electrode for electrochemical measurements depends upon the achievable potential window (range). HMDE has a much wider potential window than a bare GCE. However, if you coat your GCE with mercury film to form a GCMFE, you can achieve similar potential range to a HMDE. If as you said the measurement you want to perform has been previously done on HMDE, you may be able to achieve the same measurement with a GCMFE. But, as others have said, I cannot understand how you achieve such measurement in a suspension as the solid particles will affect the electrode performance. Unless, you have a way of transferring your analyte into solution and removing the solid particles, it will not work satisfactorily. More information on voltammetric measurements, including the use of GCMFE, can be obtained from the attached paper,
Chapter Voltammetry – Inorganic Compounds
Normally you can use it in suspension form. But you would like to use it in cyclic voltammetry and in the presence of Carbon Black Particles (CB) in aqueous electrolyte solution. In my opinion you should check it comparing with and without Carbon Black Particles (CB) in the same aqueous electrolyte and see the interferences.
I think you can decided after this experiments if you can use it or not..
I believe this is likely to be a quite unproductive approach, but I have no idea what the goal of such an experiment would be. What particles, what redox process, what size, what pH, what potential, can there be a redox mediator?
Try a carbon-past electrode method. Mix your modified carbon particles (and bare carbon particles, if necessary) and an appropriate oil (such as a paraffin) and fill the past into an appropriate glass capillary. You simply can use this assembly as a working electrode in aqueous media.
Yes, I think you can use it. But you can avoid problems of adsorption using nafion on glassy carbon electrode. nafion improvement the electrode surface.
Carbon paste electrode is fine if you are trying to directly analyse solids not suspensions. To use with suspensions, you will need to find a way of removing the solution, drying the solid to remove residual solution and weighed to a constant weight before being used quantitatively and reliably.
i thing to check Carbon paste electrode ok if you are trying to directly analyse solids not suspensions.
Of-course you can use glassy carbon electrode for your systems, there are lots of papers discussed about glassy carbon electrode as working electrode. But you have to avoid any contamination on it.
you can make a CB particles modified electrode surface and then study the redox perperties of the desired system, using cyclic voltammetry.
Another way is to immobilized the Nafion on the electrode surface and then incorporate in it the CB for redox electrochemistry.
You can try it using an electrode with the carbon black compressed inside one cavity and perform the cyclic voltammetries. see details in my paper " Electrochimica Acta 53 (2008) 6477-6483" Madalena C C Areias
Dear Marious, You can use GC instead of HMDE but because BC has been suspended in aqueous solution, so I think that you will find noise in your measurements by CV and the repeat ability is low. I comment you that try to find a solvent for dissolving your functionalized CB such as toluene. if you run CV when the electrolyte is stirring, depend of speed of stirring and scan rate of CV, you will get different responses.
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