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# problem with calculation

calculation

8 replies to this topic

### #1 patels11

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Posted 14 August 2014 - 06:26 AM

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

### #2 mdfenko

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Posted 14 August 2014 - 07:15 AM

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

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

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### #3 patels11

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Posted 14 August 2014 - 08:00 AM

The molecular weight is 340.44.
thanks

### #4 patels11

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Posted 15 August 2014 - 01:47 AM

Please can someone show how to calculate the answer.
Thanks

### #5 patels11

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Posted 15 August 2014 - 02:30 AM

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

### #6 bob1

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Posted 15 August 2014 - 03:20 AM

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?

### #7 patels11

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Posted 19 August 2014 - 06:24 AM

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?

### #8 bob1

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Posted 19 August 2014 - 12:48 PM

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

### #9 patels11

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Posted 21 August 2014 - 12:58 AM

Thanks a lot for your help.

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