Reagent	Final concentration	Amount
NaH2PO4/Na2HPO4 (1 M, pH 7.0)	50 mM	10 mL
KCl (1 M) Imidazole (1 M) H2O	200 mM 4 mM n/a	40 mL 0.8 mL 149.2 mL
Total	n/a	200 mL