The folowing protocol can be found at http://openwetware.org/wiki/PBS.
PBS stands for phosphate buffered saline and is often used because it is isotonic to cells.
1x PBS is 137 mM NaCl, 12 mM Phosphate, 2.7 mM KCl, pH 7.4
To make 10x PBS,
- 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
- After complete mixing, top up final solution to 1 L
The pH of the 10X stock will be approximately 6.8, but when diluted to 1x it should change to 7.4. Measure it using the ph-meter and, if necessary, pH can be adjusted using hydrochloric acid or sodium hydroxide.
- 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%.