# 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 5**pmol** 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!

Asking for your help as usual...10Q

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)

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!

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