DNA-conc. in solutions

Arnoud van Vliet avvliet at knoware.nl
Mon Feb 21 17:14:28 EST 2000

Measuring the OD280 is only done to estimate the amount of contaminants in
the DNA. When the OD260 is 1, then it is only 50 ug/ml when the ratio
260/280 = 1.8 or higher. So if it's lower, then the formula is not correct.

Look in Sambrook, Molecular cloning in the appendices


<a_firzinger at my-deja.com> wrote in message
news:88r4q0$rk8$1 at nnrp1.deja.com...
> I usually measure DNA-conc. by determining OD at 260nm and
> 280nm. Usually I assume 50µg/ml ds DNA at OD260 of 1.
> However, I know that there is a formula existing, which
> includes the OD measured at 280nm. Maybe someone of you
> remembers it and could send it to me. I just know a
> formula for protein concentration which includes
> OD260nm and 280nm:
> Prot.conc.(mg/ml)= E280 x 1,56 - E260 x 0,757
> Regards,
> Andreas :-)
> Sent via Deja.com http://www.deja.com/
> Before you buy.

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