Recommended resuspension buffer
For the stock solution we recommend 10 mM Tris-EDTA pH 8.0.
To make the working solution, we recommend to dilute the stock solution with Tris-buffer. This lowers the EDTA concentration that may disturb in enzymatical reactions.
The buffer concentration should be adjusted to the corresponding amount of oligonucleotides as DNA has a relatively high acid strength of its own. This buffer is equivalent to the buffer systems that are currently used for molecular biological applications such as PCR or sequencing.
We do not recommend dissolving our Salt Free and HPSF oligonucleotides unbuffered in distilled water. Due to the salt free properties of these oligos, no buffer effect is possible.
In addition, we recommend regularly checking the distilled water quality which is used for the production of the buffer.
Avoiding multiple thawing and freezing processes
After resuspension with the Tris-EDTA solution, aliquots of the oligonucleotides should be prepared and stored at -20°C. Individual aliquots can then be kept in liquid form at +4°C if they will be consumed within 1-2 days.
If long-term storage is required (> ½ year), it is recommended to store the samples at -80°C free of water (lyophilised) to exclude any enzymatic activities. Long-term storage at -20°C is not adequate because the exclusion of any enzymatic reaction can't be guaranteed.
From our experience, oligonucleotides can be stored between one month and two years depending on their individual properties and their different intended purposes and handling.
Because of the variations in oligo properties, applications, and handling, we can not give a definite shelf life guarantee.