Science Buddies: "Ask an Expert"

I built the gel electrophoresis chamber shown in the Forensic Science project. The first trial went fine and worked pretty well. I did additional trials and noticed that the agar solution at the positive electrode end got brown/yellowish and the discoloration grew as I continued running the electricity. Why did this happen? The only thing I can think of, is I reused the wire electrodes instead of using new ones each time. I noticed the positive electrode got sort of corroded, not rusty, but corroded. The negative one did not. I also tried a paperclip instead of the wire that came with the kit I purchased, which I assume was stainless steel, per the materials list. Paperclips are not stainless steel, they are galvanized steel based on what I researched online. Why is using stainless steel wire preferred with this process?

Thank you.
Hspartzie

Hi Hspartzie,
I am afraid I can't comment on the specific chemical reaction that's taking place in the process but it sounds like chlorine may have been generated as part of the process.

At any rate, in general terms, stainless will have better corrosion resistance than galvanized steel. (Please try the search term "corrosion resistant stainless steel vs galvanized steel" in google and I think you will see quite a few results / articles on the subject.)

Good Luck and please let us know if there's anything else we can do to help.
Willey