10 millimolar (mM) to 250 micromolar - (Aug/28/2012 )

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pito on Fri Aug 31 20:55:47 2012 said:

chandch on Fri Aug 31 17:00:46 2012 said:

Hi
I tried to understand your message (from point 3), but not sure. I will do it here to make sure I am doing in right way...

original concentration (O.D 0.4)
(Did serial dilution 10^1 to 10^9)
250 colonies at 10^6 dilution (100 ul)
In 1 ml 2500 colonies at 10^ 6 dilution. So it's 2500 X 10^6 cfu/ml
I need 1 X 10^6 cfu/ml. So I need to dilute 2500 times (I need 10 ml as total volume)
1/2500 dilution means 1 + 2499
1/250 + 2499/250 = 0.004 + 9.996 ml

Do I need to take 4ul from original stock
Am I right? Please tell me

Yes.
You are right.

However 1 more question: would you really do it like this?
Would you add 4µl into 9,996 ml?

Hi Thank you. I really don't how to calculate concentrations. I have taken as this example. Again I have one question, if the above answer is right how can we add 4µl into 9,996 ml. Because for most of experiments I do O.D reading 0.4 and from that I have to dilute it down to 1 X 10 ^6 or 10^7. And I have to take 1ml for my experiments
What is the best way? I know it's difficult if we want add 4µl into 9.996 ml (if we take this as example) Please help.

One person taught me that if I get 1.5 X 10^8 CFU/ml (original concentration), I should take 1 ml original stock and add 9ml water so it makes 10^7cfu/ml. Is it right? again taking 1 ml from this and add 9ml water, so it makes 10^6 cfu/ml. Is it right?

Thank you

-chandch-

chandch on Fri Aug 31 21:11:44 2012 said:

pito on Fri Aug 31 20:55:47 2012 said:

chandch on Fri Aug 31 17:00:46 2012 said:

Yes.
You are right.

However 1 more question: would you really do it like this?
Would you add 4µl into 9,996 ml?

If you take 1 ml of 1.5 X 10^8 CFU/ml and you add 9ml dilutant, you end up with 1.5 X 10^7 CFU/ml , you dilulted 10 times.

and you can indeed dilute it one more time and end up with 1.5 X 10^6 CFU/ml

And did you read my question about the 4µl and 9,996 ml?

-pito-

pito on Fri Aug 31 21:22:11 2012 said:

chandch on Fri Aug 31 21:11:44 2012 said:

pito on Fri Aug 31 20:55:47 2012 said:

chandch on Fri Aug 31 17:00:46 2012 said:

Yes.
You are right.

However 1 more question: would you really do it like this?
Would you add 4µl into 9,996 ml?

Thank you. Yes. I think it's difficult to add 4µl to 9,996 ml saline. Is there any way to do this?

-chandch-

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?
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-cell_bee-

chandch on Fri Aug 31 21:28:03 2012 said:

pito on Fri Aug 31 21:22:11 2012 said:

chandch on Fri Aug 31 21:11:44 2012 said:

pito on Fri Aug 31 20:55:47 2012 said:

chandch on Fri Aug 31 17:00:46 2012 said:

Yes.
You are right.

However 1 more question: would you really do it like this?
Would you add 4µl into 9,996 ml?

Thank you. Yes. I think it's difficult to add 4µl to 9,996 ml saline. Is there any way to do this?

Sorry for the late reply, but you need to make in between solutions...

for example: if you need a 1/100 dilution, its best to make a 1/10 dilution and dilute this again 10 times... to avoid the need to add a very small amount to a very large amount.

-pito-

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.

-Inbox-

cell_bee on Fri Sep 14 20:33:44 2012 said:

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.

-pito-

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.

-phage434-

phage434 on Sat Sep 15 15:27:50 2012 said:

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.

-pito-

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

-calculation-

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