Purifying RNA from Solution with RNEasy? - (Apr/04/2012 )
Does anyone know the minimum ratio of buffer RLT that you can use for the RNeasy kit? I want to purify RNA already diluted in a solution, and I don't want to use too much buffer RLT. The RNA cleanup protocol indicates you can mix 100uL of RNA in water with 350uL of buffer RLT to start, but is this the limit?
I have done purification with RNeasy a few times, and as a result I have seen that I could only obtain 1/2-1/3 of the RNA at the end. So you will get your RNA diluted even more. Buffer RLT is required for lysis of the cells. Since you have no cells in your case, I don't think it is very crucial to have high amount of RLT. However, I never done this part with low amount of RLT, so I am not 100% sure. Maybe you can try this with lower amounts of RLT with some expendable RNAs, if you have enough columns.
For info: Tech support told me that it is necessary to use at least a 3:1 (RLT:solution) ratio.