pHing TRIS-HCl without adding novel ions - (Jul/20/2001 )

I am trying to prepare 1 M Tris-HCl pH 9.0 for a custom PCR buffer, but am unsure how to adjust the pH after dissolving the Tris-HCl, which produces a pH of around 5. Is it OK to add NaOH (and thereby add Na ions) in order to raise the pH? Or should I be pHing this solution differently?
Alternatively, should I be making 1 M Tris (base) and then simply pHing with HCl? Is this equivalent to 1 M Tris-HCl pH 9.0 for a PCR buffer?

Stephen

Alternatively, you can do what we do, simply buy the right Tris mix from Sigma. They have a mix for any pH you can think of that works for Tris (7.0 to 9.1) Take a look at the big catalog page 988. They call it TRIZMA pre-set crystals. The product number for pH 9.0 is T6003. According to the catalog, these are Trisbase and Tris*HCl mixtures. This will be the easiest way for you, and will do exactly what you want.