Phosphate buffer

Phosphate buffer is often used for column chlomatography. But it is not an ideal buffer for biological assays because phosphate can act as either a substrate or a regulation factor of enzymes. Besides, the buffering ability decreases significantly at low pH. Use Good's buffers for biological assays.

Sørensen's 0.1M buffer

The preparation of phosphate buffer by Sørensen's method.

  • Sørensen, S.P.L.: Biochem Z. 21, 131 (1909) and Biochem. Z. 22, 352 (1909)
  • Gomori, G.: Methods Enzymol. Vol. 1, 138 (1955)

Mix the following volumes of A and B, and add equal volume of H2O to result [phosphate] = 0.1M.

Stock solution A0.2 M NaH2PO4
Stock solution B0.2 M Na2HPO4
A (ml)92.087.781.568.562.556.551.
B (ml)8.012.318.531.537.543.549.