Do Molarities in Chemical Solutions Refer to the Buffer Volume or Total Volume?

[tribaggili]

Hello,

I quote from a paper: "...a solution of CuSO4 (1 mM) and NaAsc (2 mM) in 10 mM Tris buffer with 20% DMSO".

Does the molarities refer to the 80% volume of the Tris buffer or of the total volume (80% v Tris + 20% v DMSO)? For example, if I want to make 100 mL solution, I have to add 80 mL of 10 mM Tris buffer, or 80 mL of 12.5 mM Tris buffer (which is 10 mM in 100 mL).

Thanks!
Andrea

 

[Borek]

No idea. I would give concentrations in regard to the total volume, but I agree it can be confusing.

Why don't you try to contact paper authors?