question on calculation DNA amount - (Jul/29/2014 )
The calculation is right.
I would trust IDT more that I would ever trust Nanodrop.
If you don't mixed up the volume. What means 23,5 x 10? You pipetted 23,5 ul ten times??
There may be something that increased the measured concentration, either in the sample or in the optical path.
I just ment I added 235 microliters (10 times the nanomolar concentration).
Ok, I knew it had to be correct but because of the weird nanodrop measurements I started doubting myself.
there may be residual buffer salts with the oligo that are increasing the reading.
But that is unlikely in commercial oligos. Desalting is the standard purification procedure.
The A260 by nanodrop should be arithmetically identical to the value supplied by IDT. IDT determines mass from the extinction coefficient of the oligo. Nanodrop determines mass without regard to base composition, therefore it is not reliable for oligos because there is no allowance ACGT.