# Help with primer concentration for sequencing - (Sep/05/2014 )

Hi everyone.

I just want to run something by people more experienced than me: I have to send a plate for sequencing at an outside facility and I want to send an adequate amount of primer. They say that 20ul with concentration of 10pmole covers 5 reactions. My primer stock concentration is 25uM, how much should I send so that they have enough primer to run my sequencing reactions?

If I dilute my stock to 10uM and send 10ul at that concentration, is that enough? I mean, 10uM means that there's 10 micromoles in that 10ul volume. Since 10 micromoles = 10000000 picomoles, then I'm sending much more than they need... is that correct?

Thanks!

-aristotle-

No!  10 uM is a concentration. It means 10 micro moles of substance in 1 liter volume. If you are sending 10 ul, that is 10**-5 of a liter, so you are sending 10**-5 moles/liter * 10**-5 liters = 10**-10 moles, or 100 pico moles.

Note that 10 uM is the same as 10 pmol/ul.

Note that your sentence "They say that 20ul with concentration of 10pmole covers 5 reactions." makes no sense. You cannot have  a concentration of 10 pmole. It is an amount, not a concentration.

-phage434-