Calculation help! - (Jun/14/2008 )

I need to prepare 100ul of 10mM Tris/Cl, 1mM EDTA, pH 8 buffer from stock solutions. How can I do this if the stocks were: 100mM Tris/Cl, pH8; 500mM EDTA?

Thanks in advance!

I'd use the V1 x C1 = v2 x c2 formula for this kind of stuff

V1(?) = unknown volume of stock we need to make the solution
C1 = concentration of stock we make it with

v2 = volume that we need of the solution we are making
c2 = concentration of the solution we are making

we need to make 100microlitres 10mM Tris/Cl

we have 100mM Tris/cl stock


V1(?) x C1 = v2 x c2

V1(?) x 100mM = 100microlitres x 10mM




V1(?) = 100microlitres x 10mM
----------------------------
100mM



cancel the units out



V1(?) = 100microlitres x 10
-----------------------
100


V1(?) = 10microlitres

If you do the same for the EDTA I think you come up with 0.2microlitres which is a really small amount. Perhaps you may need to dilute the stock 1/10 and take 10x as much (2microlitres). Am I on the right track?

yes