# problem with calculation - (Aug/14/2014 )

Hello. Hope you are well.
I was wondering if someone could help me with what may be very smple.
I have 10mg DPO-1. Due small quantity i feel it's best to add liquid to the bottle. so I add 1ml EtOH i will have concentration of 10mg/ml also equivalent to 10ug/1ul. Please can someone tell me how I can make 1mM solution from the stock of 10mg/ml.
thanks

-patels11-

what is the molecular weight (or formula weight) of dpo-1?

moles=weight/molecular weight, molarity=moles/volume.

-mdfenko-

The molecular weight is 340.44.
thanks

-patels11-

Thanks

-patels11-

Hello I think I have worked it out
the stock concentration / mw
=
10mg/ml / 350.44 = 2.937x10^-7M
The problem is my stock is too diluted please can someone suggest the volume I should reconstitute the DPO-1so I could get a stock of around 100mM or higher.

For your information I need to add 30uM of DPO -1 to 10mls for my experiment.
Thanks

-patels11-

No - use the formulae Mdfenko supplied.  Units are important! M=mol per litre!

10 mg = 10/1000 g.  10 ml =10/1000 litres

number of moles =mass (g)/molar mass (g/mol).

=0.01 g/350.44

=...?

c (mol/litre)=number of mol /v (litres)

=.../0.01

=? mol/l

or how much mmol/l?

-bob1-

0.01/350.44 =2.85 X 10^-5

2.85 X 10^-5 / 0.01 = 0.00285M = 2.8mM

Stock volume is 10mls. Is this correct?

-patels11-

Yes, this is correct for a 10 ml volume - that's what the 0.01 part of the second equation is 10 ml/1000 ml =0.01 l

-bob1-

Thanks a lot for your help.

-patels11-