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# Makin' a couple of dilutions. watch

1. I want to make a 1/400 dilution of blood in 0.33M Sodium Chloride using two serial 1/20 dilutions.

How’d I complete this dilution series in micro-tubes starting with 50µl of blood?

Thanks.
2. What standard chemistry is this?
Degree level?
Just wondering out of curiosity
3. (Original post by HKSR)
What standard chemistry is this?
Degree level?
Just wondering out of curiosity
Yes it's degree level.
4. Bump
5. (Original post by hollywoodbudgie)
I want to make a 1/400 dilution of blood in 0.33M Sodium Chloride using two serial 1/20 dilutions.

How’d I complete this dilution series in micro-tubes starting with 50µl of blood?

Thanks.
How much do you need and do you need to use all of the blood? If so:

Take your 50µl of blood and add 950µl 0.33M sodium chloride solution.

Extract a 50µl this sodium chloride solution and blood mixture. To this extract add another 950µl of sodium chloride solution.

Result: 1/400 dilution of blood in a 0.33M sodium chloride solution.
6. (Original post by js374)
How much do you need and do you need to use all of the blood? If so:

Take your 50µl of blood and add 950µl 0.33M sodium chloride solution.

Extract a 50µl this sodium chloride solution and blood mixture. To this extract add another 950µl of sodium chloride solution.

Result: 1/400 dilution of blood in a 0.33M sodium chloride solution.
You've been very helpful to me, but I'm really lost here. Where'd the 950 come from?
7. (Original post by hollywoodbudgie)
You've been very helpful to me, but I'm really lost here. Where'd the 950 come from?
You want to dilute 1/20 then 1/20 again to get 1/400.
1/20 means that for every one part of 'a' you need 19 parts of 'b'.
As you have 50µl of blood you need 19 times that of sodium chloride solution.
19*50 = 950
8. (Original post by js374)
You want to dilute 1/20 then 1/20 again to get 1/400.
1/20 means that for every one part of 'a' you need 19 parts of 'b'.
As you have 50µl of blood you need 19 times that of sodium chloride solution.
19*50 = 950
Thank you so much!
9. (Original post by js374)
How much do you need and do you need to use all of the blood? If so:

Take your 50µl of blood and add 950µl 0.33M sodium chloride solution.

Extract a 50µl this sodium chloride solution and blood mixture. To this extract add another 950µl of sodium chloride solution.

Result: 1/400 dilution of blood in a 0.33M sodium chloride solution.
Hello. Just wondering if you could help me with this question:
http://www.thestudentroom.co.uk/show...89&postcount=1

Thanks!

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Updated: January 23, 2011
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