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# 10 millimolar (mM) to 250 micromolar

Bacteria CFU

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### #46 Inbox

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Posted 15 September 2012 - 02:55 AM

This means you have to take 1ml of 10^6 dilution stock is of 2.5*10^9 CFU/mL. and 9ml of dilution solution this makes 10^7 diltion stock is of 2.5*10^8 CFU/mL. and
then take 1 ml from above to again dilute it by adding to 9ml diution solution. so you will be getting 10^8 dilution stock is of 2.5*10^7 CFU/mL.

10^8 dilution stock is of 2.5*10^7 CFU/mL.
Add 40ul of 10^8 dilution stock is of 2.5*10^7 CFU/mL. to 9960ul to make upto 10ml.

For cross checking check below,
2.5*10^7 CFU/ml ------ 1000 ul
so Y ------ 40 ul

Y = 10^9/ 10^3
= 10^6CFU/ml

you may again go on diluting it 100 times you can add 4ml of 2.5*10^5 CFU/mL to 6ml of diluting solution.

Edited by prabhubct, 15 September 2012 - 04:38 AM.

### #47 pito

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Posted 15 September 2012 - 03:57 AM

Hello,
I am a very new person to cell culture and would need some help with the calculations...
1. I am testing few inhibitors on mouse cellline. I have a chemical compound whose MW is 243. I need to dissolve it in DMSO and get the concentration to 10mM. Then I need to dilute it to 200uM and serial dilute this to 20uM-10um-5um-2.5um and so on...
How do I do this and when serial diluting it, do I have to use the growth media or do I use DMSO? I do not want the concentration of DMSO to go more than 1%. Please help

2. I have BMP4 whose concentration is 10ug/ml. I need 10ul of this, whose concentration is 250pM. How do I calculate?

what you know: MW= 243
what you want: 10mM , meaning 10 moles/m³ or 10^-2 moles/liter

so how to solve it?

243 grams/mole , you need 10 moles/m³ or 10^-2 moles/liter.
so if you want to make 1 liter, you need to take 10^-2 moles and you know its 243 grams/mole, so you should be able to figure out how many grams you need to take...

Are you sure you need such small amounts?

And no: you only dissolve it a bit of DMSO and add this to the growth medium. So if you make (for example) 1liter, you make 0,99 liter (for example) of growth medium with 0,01liter DMSO (not sure how well it will dissolve.. this depends .. so you need to try this yourself).

Same goes for the second queston; write down what you have and what you want... see how far you can come.

Edited by pito, 15 September 2012 - 07:34 AM.

If you don't know it, then ask it! Better to ask and look foolish to some than not ask and stay stupid.

### #48 phage434

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Posted 15 September 2012 - 07:27 AM

1 molar is not 1 mole/m^3, but rather 1 mole/liter. So, 10 mM is 10^-2 moles/liter, or 2.43 g/liter.

### #49 pito

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Posted 15 September 2012 - 07:33 AM

1 molar is not 1 mole/m^3, but rather 1 mole/liter. So, 10 mM is 10^-2 moles/liter, or 2.43 g/liter.

Ah yes, I missed a factor 1000.
Ment to say: 10mM , meaning 10 moles/m³ or indeed 10^-2 moles/liter.

If you don't know it, then ask it! Better to ask and look foolish to some than not ask and stay stupid.

### #50 calculation

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Posted 16 October 2012 - 06:56 AM

it should be 10 mM (millimolar) to 250 uM ( micromolar)
How should i dilute it to reach the desired volume?

### #51 hobglobin

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Posted 16 October 2012 - 07:42 AM

http://www.promega.c...th/dilution.htm

One must presume that long and short arguments contribute to the same end. - Epicurus
...except casandra's that did belong to the funniest, most interesting and imaginative (or over-imaginative?) ones, I suppose.

### #52 calculation

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Posted 16 October 2012 - 08:35 AM

can you please guide me on how to use the calculator?

Protip: Understand what you are doing before you rely on programs/webpages... Also merged with rest of the dilutions/calculations thread... Bob.

### #53 Smog187

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Posted 16 October 2012 - 09:03 AM

You could always use the old C1V1=C2V2: (10mM)(V1)=(0.25mM)(V2). Insert the final volume you want for V2 and solve for V1. This tells you that you need to add a certain amount of V1 to get the concentration at C2.

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Posted 17 October 2012 - 12:47 PM

In the above calculator, just input stock as 10, desired working concentration as 250 and volume of working solution = how much you want in the final volume, for ex if you want 50 ml put 50 ml. It would give you a value say 0.9833 so take 0.9833 of your stock i.e. your 10 mM solution and add water to it to dilute it.