After doing electrophysiology for quite a few years, I was asked a
fundamental question that I realized I could not answer.
When you AgCl a Ag wire for electrophysiolgy, I have been taught that a
black coating is desirable. When I coat my wires I constantly reverse the
polarity of the wire being coated, and it alternates between a gray andblack
coating. I take the wire out after leaving it in the black coating phase for
My question is: What is the difference between the gray and black coating?
I get the gray coating when my wire is postive, thus I presume the
Cl- is being plated on. Why is the black coat desirable?
For your info I AgCl my wires in weak HCL using a 1.5 V D battery with a
polarity switch on it.
Thanks for any info, e-mail preferred.
Trent A. Basarsky tab at iastate.edu
Department of Zoology & Genetics
Iowa State University
Ames, Iowa 50011