RNA purity

 I would like to ask, if my 260:280 ratio is between 1,95-2 is it still necessary to treat my RNA with DNAse? and how mazy times can I thaw and freeze my isolated RNA? Only once? Two or three times will destroy my RNA?
Thanks in advance :)

Hi Petroula T,

Yes, you should treat your RNA with DNaseI and remeasure the A260/280 because this method of quantification includes all nucleic acids that are present (both DNA and RNA).

I have obtained similar results with RNA thawed 3 times, although I tend to just thaw it once and make several batches or one large batch of cDNA that will last me through multiple experiments.

Thank you very much hcheung :) I also read somewhere that cDNA is also very sencitive and that we should not thaw and freeze it more than once. I guess that's true. What's your opinion?

I have not heard that. I try not to thaw my samples more than 10 times, multiplexing whenever possible. Anyone else with thoughts on this?