PBS

Purpose

PBS stands for phosphate buffered saline and is often used because it is isotonic to cells.

Recipe

1x PBS is 137 mM NaCl, 12 mM Phosphate, 2.7 mM KCl, pH 7.4

To make 10x PBS,

1. Combine the following:
   • 80 g NaCl
   • 2 g KCl
   • 14.4 g Na₂HPO₄ (dibasic anhydrous) OR 18.1 g Na₂HPO₄ · 2H₂O (dibasic dihydrate) OR 27.2 g Na₂HPO₄ · 7H₂O (dibasic heptahydrate)
   • 2.4 g KH₂PO₄ (monobasic anhydrous)
   • 800 mL distilled H₂O
2. Adjust pH to 7.4 with HCl
3. Add H₂O to 1L
4. Autoclave for 20 minutes on liquid cycle. Store at RT.

• PBST: For some applications (washing) one adds Tween 20 PBS which makes PBST
  • Usual concentrations of Tween 20 in PBST are 0.1 or 0.05%.
  • Usual concentration of Triton X-100 in TBST is 0.1-0.3%.

Other Links

• Silver: 10x PBS
• wikipedia article