shelf life of dNTPs at -20°C

Bryan L. Ford fordb at bcc.orst.edu
Tue Mar 3 23:44:49 EST 1998


Michael Vagell wrote:
> 
> Does anyone know how long deoxynucleotides (dNTPs) can be stored at -20°
> Celcius? I have some aliquots of deoxynucleotides that have been kept at
> -20° C for four years. Are they still usable, or should I get some new ones?

Michael:

In a word, yes. If they were high quality when new, then they should be
just fine after this storage... based on my personal experience. (Be
aware that some brands have a better reputation than others, and that
this reputation may be deserved; we have had good results with
Boehringer-- no affiliation of mine). I also find that diluted mixed
dNTP sets (e.g. stock with 2.5 to 25 mM for each dXTP) are functional in
PCR for at least a couple of years if stored at 4 degrees C. I
personally suspect that more than a few freeze/thaw cycles may not be
good-- but even this damage should be prevented by "snap" freezing in
LN2, or in -80 degree ethanol, before placing in a -20. If you are doing
demanding work such a really long PCR, that is above 15 kb expected
products, or work which seems to give weak products for one obscure
reason or another, then you may well see improvements from changing dNTP
brand or freshness.

Bryan



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