I am trying to find a buffer solution to keep geneblock/ultramer calibration standards for qPCR quantification. I have seen variability with water and tween when stored at 4C for two days. I am trying salmon sperm and tween with some luck, but there is variability in the lower copy dilutions (100-2 copies). I skimmed through this paper: Impact of Long-Term Storage on Stability of Standard DNA for Nucleic Acid-Based Methods. I tried the 50% in water but my results are terrible. I am wondering if this is because of the different enzyme? or template they are using gDNA and I am using sythetic oligos? For the record I am using molecular grade water and glycerol.
i would use TE buffer for DNA. Aliquote to working volume such as for 2-3 experiments in 1 tube and store at -20. Good luck!
There are reports that storing DNA in 50% glycerol helps to significantly reduce degradation with a frequent freeze-thaw cycle. However, I do not know exactly why this technique is not very popular.
https://www.ncbi.nlm.nih.gov/pubmed/17721323
Probably, in my opinion, there is a difficulty in what concentration of DNA is best stored with glycerol. It is not very advisable to store low-concentrated working solutions, for example, 20 ng / μl, due to the possible inhibition or change in the physicochemical properties of the PCR reaction or other reaction (for example, when measured by Qubit). In addition, in the case of storage of stock DNA solutions, it becomes difficult to measure using spectrophotometers, in particular, Nanodrop analogs, since glycerin can lead to difficulties in cleaning it from mirrors and sensors.
In addition, it is possible if stock DNA is stored, the preparation of working DNA solutions will be difficult to obtain accurate dilutions.
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