I am working with samples of cryopreserved DNA in different years of a Biobank, so when I am going to measure the concentration or purity of DNA, a big problem arises. This is that there are no records of what are the types of eluents in which DNA is dissolved. therefore I need to know if there is a way to normalize the measurements with a blanking solution?
Dear Viviana, In your situation I would use Qubit for fluorescent detection of DNA concentration. It is very simple and fast way that not depends on solution nature. If you haven't an opportunity to use Qubit (or analogue), try 10 mM Tris buffer with Ph 9.0, 1x TE buffer, and deionized water as a reference (blank) and compare. More over, You can try agarose gel (0.8%) and corresponding size od DNA ladder. Some gel-doc equipment can calculate concentration by fluorescence.
hi
DNA sample is plasmid or genomic DNA ?
1- you can dissolved DNA in 50 ul DDW and then 2 times assay by nano drop A-one time DDW as control B- second time TE-buffer as control
2- Run 0.2 ug of DNA sample beside the 0.2 ug of sample with a certain and exact concentration on 1% agarose gel .you should see same band intensity from your sample with control sample .
good luck
If there is only the question on measurements, I would also follow the recommendations by Andrei S. Babenka.
However, keep in mind, that working with samples of unknown processing (and in this case possibly also even sampling if I am right) may surely rise questions on the reproducibility, interpretation and scientific quality of the results (what would you write in methodology?). It may eventually affect the possibility to publish such results. It should be always recommended to check all possible preanalytical variables, and missing data on sample collection and processing are those of high importance.
Good luck.
I thank you all for your recommendations, they are a great help to me.
With respect to Reza Hadavi's question, the samples are of genomic DNA.
At biobanks, the more used buffer to store genomic DNA samples are TE buffer (10mM TRIS - 1mMEDTA pH 7-8) for long term storage. If the extraction method used was columns of ionic interchange, salting-out or magnetic-beads,..., DNA Hydration solution (=TRIS-EDTA=TE) maybe probably your choice.
The lowest used method for long term storage of gDNA was water (it´s ussually used for RNA storage) but PBS is another possibility.
Try to meassure in your Nanodrop with PBS and with TRIS EDTA as a blank: the DNA samples don´t differ in a low as 2-5%.
Don´t forget that if you compare a UV meassure with a Picogreen meassure you can observe big differences. The last one will be a bit lower as 80% or more than observed with Picogreen.
Qubit is a great choice but if you haven´t one you can do anything
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