3 replies to this topic

[zack]

hi admin and chatter,
i need some help to prepare stock solution from above,
how to calculate 50mm Tris  to 5ml volume 1 M tris.

what i know

M.W for Tris is 121.14g
1 M = 1000mM

then,

121.14g X 5000mM / 1000mM = 605.70g/L
to make 100ml, 605.70g/100 = 6.05g in 100ml

but i have on idea from calculation above to make final volume 5ml 1M Tris.
pls solve my problem

thank you

Edited by zack, 26 June 2009 - 10:01 AM.

[pito]

I do not understand you really, are you sure you got the task correct? Because as I see it it says that you need 5ml of a 1M tris solution to get a 50mM solution in total (in 100ml)
ex: 8ml of a 5M NaCl sulotion is in 100ml ===> 8/100 * 5 = 0.4M

You have for each 100ml 5ml of a 1M tris solution to get a 50mM solution in total.

If you now need a 1M solution in total then you need..... ml of a 1M solution...?


ex. if you need 0.25ml of a 1M tris bottle to get a 0.1M solution in total, how much of this bottle do you need to use to get a 0.2M solution in total?

its simply x2 .... (keep in mind you need to take in this factor for the other substances to

[zack]

pito, on Jun 26 2009, 10:52 AM, said:

I do not understand you really, are you sure you got the task correct? Because as I see it it says that you need 5ml of a 1M tris solution to get a 50mM solution in total (in 100ml)
ex: 8ml of a 5M NaCl sulotion is in 100ml ===> 8/100 * 5 = 0.4M

You have for each 100ml 5ml of a 1M tris solution to get a 50mM solution in total.

If you now need a 1M solution in total then you need..... ml of a 1M solution...?


ex. if you need 0.25ml of a 1M tris bottle to get a 0.1M solution in total, how much of this bottle do you need to use to get a 0.2M solution in total?

its simply x2 .... (keep in mind you need to take in this factor for the other substances to

thank.. i'm forget something

1 M tris , 5 M Nacl, 0.5 M EDTA and 10% sds is a Stock solution , so i  need 50mM tris from 1 M €Tris stock solutions,

in 1 M Tris i should take 5ml of 1 M Tris to make 50mM, in TOTAL VOLUME 100ml

yes u are right..

thank for explanation

Edited by zack, 26 June 2009 - 11:19 AM.

[pito]

yeah, indeed.

So I do not think you need to recalculate anything, its allready given how much you need to put in a 100ml solution to get the correct buffer.