When calculating the concentration of Tris(hydroxymethyl)amino methane buffer solution, which consists of Tris, HCl and water, should the concentration be calculated with the amount of substance of Tris only or should also the amount of substance of HCl to be taken account when calculating the buffer concentration?
Generally I would expect the concentration to be expressed in molar terms so there is no difficulty
Hi Anna-Kaisa,
typically these buffers are produced as equimolal solutions. This means you add TRIS and HCl in a ratio of 2:1, which results in a solution with a 1:1 ratio of TRIS:TRISH+. Like this you achieve the highest buffer capacity. For seawater the most common concentration is m(HCl) = 0.04 mol kg-1, to which you add 0.08 mol kg-1 of TRIS. An excellent reference is DelValls & Dickson (1998).
If you provide me with the recipe you want to use, or the publication you are referring to, I might be able to guide you through the preparation procedure.
Good luck - Jens
- Badges
- Science method