What is the recommended solution in which to store RNA samples that will be used as templates for cDNA synthesis?
For best results, all RNA samples should be suspended in RNase-free water. Alternatively, RNase-free 1 mM sodium citrate (pH 6.5) or 10 mM Tris buffer (pH 7.0) may be used. Do not use DEPC-treated water, as most DEPC preparations are contaminated with molecules that are inhibitory to reverse transcription and/or PCR. For long-term storage, RNA preps may be stored at -70 ºC in RNase-free water, or the buffers listed above, or precipitated in ethanol or isopropanol. In order to avoid repeated freeze-thaw cycles, it is recommended that frozen RNA samples be stored as multiple, single-use aliquots.