glycerol and sucrose in loading dye - (Apr/06/2006 )
I would like to know what is the difference when you have glycerol or sucrose as "sinking" agent for DNA samples in the loading dye? And at what percentage for both the agents to be appropriate?
There is not much difference. I think the glycerol is harder to pipet. We use neither, and mix our loading dye from 15% Ficoll-400 (Sigma) which has the advantage of being stable at room temperature.
We also use Orange-G dye rather than Bromophenol Blue and Xylene Cyanine Blue dyes. Orange G runs at the front of the gel, and does not obscure DNA samples when imaging the gel.
Glycerol and sucrose makes the sample more dense than the sample buffer, so the sample will remain in the bottom of a well rather than floating out.The difference between glycerol and sucrose is based upon their viscosity, Glycerol is superior to sucrose as a viscosity agent but Sucrose is better than glycerol for increasing density, because sucrose is less sticky.
GLYCEROL - 30%
SUCROSE - 40%
Thank you so much.