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The Laboratory Notebook

Articles on The Laboratory Notebook

Primary reference: Brautigan, D.L.; Ferguson-Miller, S.; Margoliash, E. Methods in Enzymology 1978, volume 53D, pp 131-132.

A. Preparation of 0.076 M Sodium Phosphate Buffer, pH 7.0

B. Preparation of 250 mL of 0. 15 M Na2HPO4

Calculation: 0.15 mol/L * 0.25 L * 141.96 g/mole = 5.324 g needed

I weighed 5.3240 g Na2HPO4 and transferred it quantitatively into a 250 mL volumetric flask to which I added distilled H2O to the mark. I mixed the solution 20x by inversion.

C. Preparation of 250 mL of 0. 15 M H2NaPO4

Calculation: 0.15 mol/L * 0.25 L * 130.99 g/mole = 5.175 g needed

I weighed 5.1750 g H2NaHPO4.H2O and transferred it quantitatively into a 250 mL volumetric flask to which I added DI H2O to the mark. I mixed the solution 20x by inversion.

D. Preparation of 500 mL of 0. 076 M Sodium Phosphate Buffer, pH 7.0

I combined 97.5 mL of 0.15 M NaH2PO4 (part A) and 152.5 mL of 0.15 M H2NaPO4 (part B) in a 300 mL beaker and measured the pH. The pH was 6.96 so I transferred the solution to a 500 mL volumetric flask which I then filled to the mark with DI H2O. The pH was 6.99 . I stored the buffer in the cold room.