[DIYbio] Re: Non-Platinum Electrophoresis Electrodes That Don't Degrade

I've been working on this problem, too. I'm trying the graphite approach. Electro-discharge machining (EDM) is the source I've been exploring for graphite. It's very cheap. There are grades with no fillers added. 100% carbon. The big problem is sealing the liquid in at the box connector point. Here are a few of the sources I've used:

http://www.graphitestore.com/index.asp

The main problem with graphite seems to be electrolysis creating gas bubbles that break apart the layers creating a film of carbon bits in the buffer and clogging up the gel. Here is a decent paper on the mechanics of electrolysis in the graphite:
http://www.scielo.br/scielo.php?pid=S1516-14392014000100012&script=sci_abstract
Since I'd like to minimize electrolysis, this paper gives some clues for experimental design.

Here is a discussion thread on connecting copper connector to a graphite rod.
http://cr4.globalspec.com/thread/12335/How-to-connect-copper-wire-into-carbon-block

Here is a table of material parameters of different EDM graphite grades:
http://dev.mkprogramming.com/mwi/wp-content/uploads/2014/10/EDM_ECGrades.pdf

I tried taking the Pt electrode out of the conventional BRL gel box to use as a pattern to cut an L-shaped graphite electrode out of the softer graphite. It's just a few nut thread turns too thick to place the cut-out graphite back in the electrode position in the box. I'd love to find the screw/nut connector with about another 3-4mm more of thread. I think I could get a seal with that.

I'm still working on my electrophoresis system but, with the graphite electrodes, the cost of the electrodes is not my foremost problem anymore.

Cindy

On Sunday, May 26, 2013 at 11:29:19 AM UTC-7, Josiah Zayner wrote:

I have been testing out a bunch of different metals and they either oxidize to death on the minutes timescale or in the case of stainless steel turn the buffer orange/brown.

Platinum wire is pretty expensive ~$1.00 cm^-1. Has anyone had luck with a cheaper metal at 100V or greater with TAE?

I have tried:

Nickel

Stainless Steel 430

Tinned Copper

Thinking of trying Titanium or Nickel Titanium (<= $4 meter^-1). Anyone ever tried these?

Thanks,

     Josiah Zayner

http://DoItOurselfScience.blogspot.com