Phosphate-buffered saline (PBS)

Reagent	Amount to add (for 1X solution)	Final concentration (1X)	Amount to add (for 10X stock)	Final concentration (10X)
NaCl	8 g	137 mM	80 g	1.37 M
KCl	0.2 g	2.7 mM	2 g	27 mM
Na2HPO4	1.44 g	10 mM	14.4 g	100 mM
KH2PO4	0.24 g	1.8 mM	2.4 g	18 mM
If necessary, PBS may be supplemented with the following:
CaCl2·2H2O	0.133 g	1 mM	1.33 g	10 mM
MgCl2·6H2O	0.10 g	0.5 mM	1.0 g	5 mM

PBS can be made as a 1X solution or as a 10X stock. To prepare 1 L of either 1X or 10X PBS, dissolve the reagents listed above in 800 mL of H₂O. Adjust the pH to 7.4 (or 7.2, if required) with HCl, and then add H₂O to 1 L. Dispense the solution into aliquots and sterilize them by autoclaving for 20 min at 15 psi (1.05 kg/cm²) on liquid cycle or by filter sterilization. Store PBS at room temperature.