25 mM Tris-phosphate (pH 7.8) - (Mar/12/2005 )

how can i make this buffer? i know how to make Tris- HCl buffer, but how about this one? what is the acid and base here?

25 mM Tris-phosphate (pH 7.8)

any ideas?

thanks.

Neutralizing tris base with phosphoric acid (H3PO4) seems likes the obvious choice.

Yep, I agree with serge. I've never made tris-phosphate buffer, but I've used Tris-phosphate-EDTA (TPE) for electrophoresis, and is Tris base and phosphoric acid, plus, in this case, EDTA. So I gues tris-phosphate is just Tris, with the pH adjusted with phosphoric acid.

10X TPE (Tris phosphate)
108 g Tris base (Final- 89 mM on 1xTPE)
15.5 mL 85% phosphoric acid
10 mL 0.5 M EDTA, pH 8.0
dH2O to 1 L

Hope that helps!