We know that the pH value of Tris-Cl buffer often changes when the temperature is different. Usually, we adjust the pH value at room temperature(25℃). But, my buffer always used at 4 ℃.Then, my question is at which temperature should I fix the final pH value?
Usually you make your Tris buffer at room temp for a 25C pH that will temperature-adjust to the pH you want at 4-5C. The rule of thumb is that, between 25C and 5C, the pH of a Tris buffer will increase by 0.03 pH units per degree fall in temperature. So, if you want pH 7.6 at 4C, prepare the buffer at pH 7 at room temperature. If you need pH 7 or so at 4C, you might want to use another buffer as Tris won’t behave well at 4C for that pH–that is, it won’t be a very good buffer. There are tables for more exact temperature compensations. Here is one: http://www.neb.com/nebecomm/tech_refere … buffer.asp
