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Initial Publication Date: August 5, 2005

Living in the Microbial World

How to make 10x Phosphate Buffered Saline, pH 7.4

(0.2 M phosphate, 1.5 M NaCl)


Materials
  • 2.28 g NaH2PO4 (mw=120; 0.038M) or 2.62g NaH2PO4(H2O) (mw=137.99; 0.038M)
    (Note: monobasic!!!)
  • 11.5g Na2HPO4 (mw=141.96; 0.162M)
    (Note: dibasic!!!)
  • 43.84g NaCl

How to:
  • Add NaH2PO4 and Na2HPO4 and NaCl to 450 ml dH2O.
  • Adjust pH to 7.4 by adding dilute (1N) HCl if necessary.
  • Bring the final volume to 500 ml with water.
  • Dilute 1:10 for final concentration.

Tip for sterilizing toothpicks without an autoclave (for innoculating cultures or streaking plates)
  • Cook in regular oven 275F for 1 hour, wrapped in tin foil!