*RNA may be stored in several ways.
Short Term Storage
*Store RNA in RNase-free H2O (with 0.1 mM EDTA) or TE buffer (10 mM Tris, 1mM EDTA).
*RNA is stable at -80° C for up to a year without degradation.
*Note that Magnesium and other metals can catalyze non-specific cleavage of RNA. These can be chelated by the addition of EDTA if RNA is to be stored and retrieved intact.
* Important!: use an EDTA solution known to be RNase-free for this purpose (older EDTA solutions may have microbial growth which could contaminate the RNA sample with nucleases).
* RNA solubilized in formamide solution can be stored at -20°C without degradation for at least 1 year (Chomczynski, 1992).
Long Term Storage of RNA
RNA samples may be stored at -20°C as ethanol precipitates for long periods of time.
However, accessing these on a routine basis can be a nuisance, as the precipitates must be pelleted and dissolved in an aqueous buffer or water (Rnase-free) before pipetting.