Hey Greg,

Depends on the material you're using.

If you have a Ag (Silver) wire as stimulating and recording electrode, definitely adding the AgCl layer by anodization is good a idea for both stability and the SNR.

A saturated aqueous KCl solution will do the job for the AgCl deposition on the Ag electrode. You can use a lab power supply or potentiostat.

If you use a different type of metal (Pt, Au, Ir) I would electrodeposit a layer of IrOx for the same reasons.

Hope it helps,

R

Hi,  romeo  how did you do with a saturated KCl solution?  May you explain the 'protocol'  I am interested in.  

Manthanks Many 

For chloriding silver wires you may simply put them into bleach for ~30min. 

Dear Greg,

if you do not cover your Ag-wire (reference electrode or in patch pipette), you will have tremendous and unpredictable shifts of electric potential which will produce potentially wrong data in electrophysiological experiments measuring DC currents/voltages. So, it is necessary to use stable electrodes. Ag-AgCl is mostly used, however there others such as (i) copper-copper sulfate electrode (Cu-CuSO4) or (ii) mercury electrode (Hg-HgCl2, called calomel electrode) that we used as well. All depends on particular design of the experiments. 

Dr. Akopian suggested simple method how to cover rapidly your silver wire making Ag-AgCl elecrode. We also used successfully not electrochemical (cathode covering, using electric current) but just chemical procedures as Dr. Akopian suggested, but different methods:

1. CuSO4+NaCl solution method

2. fire melted AgCl coating

Both methods produce harder surface of coated wire and thus more mechanically stable.

Very cordially, Serguei.