3 replies to this topic

[Angrysh]

I've odered primers from IDT.

In the IDT FAQ it is suggested to add 10 microliters of water per 1 nanomole to obtain 100 µM concentration. But in my calculations the final concentration is 1µM/µL. Am I wrong somwhere? How can you possibly get micromoles (10^-6) from nanomoles (10^-9) by dilution?

This is the link to the IDT manual http://www.idtdna.co...-concentration-

Thank for help!

[phage434]

You are confusing moles with molar.  1 molar (1 M) is 1 mole per liter. The IDT instructions are 1 nanomole per 10 microliters, which is 10**-9  moles/ 10**-5 liters, or 10**-4 molar, or 100 uM.

[Angrysh]

Thank you!

Now it is clear. So molar concentration is always per liter?

[bob1]

Yes, Molar concentrations are always per litre -it's the SI unit.  It is a bit of an unfortunate thing that biologists (including myself) have gotten into  using the "M" symbol for mol/l as it is quite confusing until you know the convention.