Difference between revisions of "Cleaning and Polishing Voltammetric Electrodes"
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Suitable polishing materials can be obtained from Buehler Inc, http://www.buehler.com/consumable While automatic polishing machines might be useful if large numbers of electrode have to be polishes on a regular basis, hand polishing is more usual in a research or teaching lab. | Suitable polishing materials can be obtained from Buehler Inc, http://www.buehler.com/consumable While automatic polishing machines might be useful if large numbers of electrode have to be polishes on a regular basis, hand polishing is more usual in a research or teaching lab. | ||
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+ | If you have previously used glass body electrodes then be aware that PEEK or Teflon body electrodes need significantly less downwards pressure to be applied while polishing. Also 0.3 micron powder will cause extensive abrasion of the electrode surface which then takes a lot more polishing with 0.05 micron powder to obtain a mirror smooth finish. | ||
In short: | In short: |
Revision as of 14:12, 21 March 2013
Resist the temptation tend to over-polish the electrodes. In most cases the electrode remains clean after the experiment, or could be washed clean with suitable organic solvent to remove greasy organic materials, or dilute acid or base (0.1 mol/L HCl, HNO3, NaOH) to remove inorganics. Only if there is an intractable coating electrodeposited on the electrode, or after extended use, will the electrode need any polishing at all. Polishing should only be done if there is visually obvious surface contamination (use a magnifying glass) or where a trial cyclic voltammogram in clean solvent indicates that there has been surface contamination. Standard maintenance polishing should use 0.05 micron (or less) polishing powder, only a badly scratched electrode, or one with an extremely intractable coating would need to use 0.3 micron (or larger) powder.
Suitable polishing materials can be obtained from Buehler Inc, http://www.buehler.com/consumable While automatic polishing machines might be useful if large numbers of electrode have to be polishes on a regular basis, hand polishing is more usual in a research or teaching lab.
If you have previously used glass body electrodes then be aware that PEEK or Teflon body electrodes need significantly less downwards pressure to be applied while polishing. Also 0.3 micron powder will cause extensive abrasion of the electrode surface which then takes a lot more polishing with 0.05 micron powder to obtain a mirror smooth finish.
In short:
1. Only polish when absolutely necessary. 2. Use only light downwards pressure when polishing. When polishing manually grip the electrode at its base (ie the end where it is being polished) 3. Only use 0.05 micron powder for routine polishing. 4. Only use 0.3 or larger powders if absolutely necessary for very contaminated electrodes.
== ET069 and ET072 Leakless Reference Electrodes
The tip of these reference electrodes can become fouled with use. The tip of the ET072 can be washed or lightly polished (like a working electrode) to remove intractable adhering material, and in extreme cases you can even use a scalpel, or razor blade, to shave a thin slice from the tip, which exposes fresh polymer junction.