EtBr solution - (Mar/05/2009 )
In our lab we usually stain the gel with EtBr solution after electrphoresis. However, teh person who make sthis solution is on a conference ad I need to prepare a fresh solution. I vaguley remember him telling me to add 40ul EtBr solution in 400 ml TAe buffer. HOw do other people make their solution?
I don't put it in electrophoresis buffer, but in the gel. I do a 10,000 dilution also. (40ÁL in 400 mL)
It would depend, of course, on the concentration of your stock EtBr solution. Those recipes sound like they're assuming a stock concentration of 10 mg/ml. In any event, it's not *that* critical -- just add EtBr to the TAE until the solution is approximately as dark as it usually is when the person who's away makes it...
We also add to EtBr to gel. I use 2ul of 10mg/ml EtBr to a 50ml gel.