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What causes RNA/DNA to unbind from silica membrane? - (Mar/07/2011 )

During nucleic acid extraction using column, the RNA/DNA bind to the membrane and in the last step, eluted by buffer/water? What is in the buffer/water OR what is not in the buffer/water that causes the DNA/RNA from being released from the membrane?

-hianghao-

hianghao on Tue Mar 8 05:42:12 2011 said:


During nucleic acid extraction using column, the RNA/DNA bind to the membrane and in the last step, eluted by buffer/water? What is in the buffer/water OR what is not in the buffer/water that causes the DNA/RNA from being released from the membrane?


It has to do with salt and pH. For the DNA to bind to silica you need lots of salt and a low pH (below 7.5). To release the DNA you elute with a solution that is poor in salt and has a pH >7.5 (the EB in the Qiagen kit is at pH 8.0 I think).

-Maddie-