# Primer calculation - (May/19/2007 )

Hi guys, I am a bit lost in calculating primer concentration.

How do you convert pmol into uM?
Are Pmole and Pmol referring the same unit?

I have to work with 5pmol primer in 25ul PCR volume but I have 100uM stock primer concentration. I did the calculation assuming pmol is pico Molar but it is too llittle to measure...confused!

-Doyo-

pmol and pmole refer the pico moles of atoms.

pM and pMolar refer to the pico moles in a 1L volume.

pmole and pMolar are not the same.

Molarity and mole are related by the following equation.
(mol / Litre ) = Molar

If you are really required to work with 5 pmol for a 25ul reaction. Then your calculations should have reflected it, rather then changing to 5pM which is a different kettle of fish.

calculating volume of 100uM needed to make 5pmol
mol/v = M
mol / M = v

5 ^ -12 / 100^ -6 = v
5 ^ -8 l = v
5 ^ -2 ul = v
0.05ul

As one can not get ones hands on a 0.1ul pipette, you will have to make at the very least a 10x dilution working primer solution; thus making it 0.5ul of working primer solution (10uM)

-perneseblue-

QUOTE (perneseblue @ May 20 2007, 12:00 AM)
pmol and pmole refer the pico moles of atoms.

pM and pMolar refer to the pico moles in a 1L volume.

pmole and pMolar are not the same.

Molarity and mole are related by the following equation.
(mol / Litre ) = Molar

If you are really required to work with 5 pmol for a 25ul reaction. Then your calculations should have reflected it, rather then changing to 5pM which is a different kettle of fish.

calculating volume of 100uM needed to make 5pmol
mol/v = M
mol / M = v

5 ^ -12 / 100^ -6 = v
5 ^ -8 l = v
5 ^ -2 ul = v
0.05ul

As one can not get ones hands on a 0.1ul pipette, you will have to make at the very least a 10x dilution working primer solution; thus making it 0.5ul of working primer solution (10uM)

Thanks a lot!

-Doyo-

biomath caculator is a good way to have that. Moreover the formulas are written.

-fred_33-