Reagent	Final concentration	Amount
NaH2PO4/Na2HPO4 (1 M, pH 7.0)	50 mM	5 mL
KCl (1 M) Imidazole (1 M) H2O	200 mM 200 mM n/a	20 mL 20 mL 55 mL
Total	n/a	100 mL