I am looking for publications (or patents) stating the solubility of RNA (either total RNA, tRNA, whatever the species) in water or in saline solutions.
I don't think there is any practical limit to the solubility as long as the pH is not too acidic. The solution may get viscous, however, if the concentration gets too high, especially if the nucleic acids are long.
I agree with Adam, there will not be an upper limit..but as you keep increasing the concentration, the solution will start behaving like a jelly and becomes sticky. Due to this, it is difficult to pipette this viscous "liquid".
I do not agree :) a solution is homogeneous and there is always a limit to the amount of a product you can solubilize. Would you say that putting 1kg of RNA in 1mL of water makes a solution :)
I found some unpublished data suggesting up to 400mg/mL but I was looking for PUBLISHED data.
I totally agree with you "disagreement". Now moving on over the pedantic definition of "any upper limit" here.
400mg/ml seems to be a fair estimate(I HAVE NEVER ACHIEVED SUCH CONCENTRATIONS). Additionally i would say from that a mixture of this concentration might be far from begin a "homogeneous solution" at lower temperatures. Hence using such concentration might also be problematic. Do let me know if you are able to use a "solution" of this concentration.