Buffer is the a mixture of weak acid and its salt ( conjugate base or conjugate acid , respectively) that premits solution to resist change in pH.
In Henderson-Hasselbalch equation if the concentration of weak acid is equal to that of conjugate base, the ratio of two component is one. So, pH=pKa because the log(1)=0. In this case solution is know as best buffer.
To be honest in this case I didn't get your point, it's little confusing when I am preparing TEAP buffer.
Kindly would you help me in that case. Actually I need 0.05M TEAP buffer or solution for my HPLC analysis