Why SDS page gel have to prepared freshly? - (Jul/17/2006 )

Hi,

I am wondering why SDS page have to mix every single things freshly? If I premix the Tris buffer, acrylaminde and water in advance (eg, prepare days or weeks before and keep in 4C) and just add the APS and TEMED before I set a gel, will it make a different?

Ching

The book says that acrylamide tends to hydrolyse over time and forms acrylic acid which once incorporated into gel may effect its charge property. High pH (tris buffer), low concentration of acrylamide (diluted mixture)and temperature (RT and above) speed up the process. This may be a problem for IEF and 2-D gel, but I believe this is an overstatement for routine SDS-gel application, as long as you dont use sol'n that is too old.

Well, that's interesting. At my lab, we make the tris and the acrylamide/bis (in varying concentrations for different sorts of resolving gels and stacking) and just have it out in tubes or pump bottles on the gel bench. I have never encountered a problem with the mixes (no polymerization issues, and barring user error, all gels seem uniform as far as standards go), and I wasn't even here when the last batch of solution was made (I started in May). This is a 10-gel-a-week operation around here, and we make up a bunch of solution and gels all the time and store them for a long while with no problem.

Methinks perhaps published PAGE protocols are a bit strict . . .

Agree, there are many pre-made PAGE gels that last for long, long time.

We buy precast gel from BIO-Rad which one can store for 1-2 months at 4C.

... yes but some pre-cast gels contain azide if I'm right.