# Determining pH of immunoprecipitation buffer recipe

I'm following a protocol for extraction of proteins from yeast, and I came across this recipe for immunoprecipitation buffer:

$\pu{50 mM}$ HEPES-$\ce{KOH}$, pH 6.8, $\pu{150 mM}$ $\ce{KOAc}$, $\pu{2 mM}$ $\ce{MgOAc}$, $\pu{1 mM}$ $\ce{CaCl2}$, $15\%$ glycerol.

Does this mean I bring the whole solution to pH 6.8, or do I make the HEPES at pH 6.8, and then add the remaining reagents?