ChemHBuffer Calculator

0.1 M Sodium Phosphate Buffer Calculator

Scale six fixed 0.1 M sodium phosphate presets made from defined 1 M monobasic and dibasic phosphate stocks.

Select a reviewed preset and enter the final volume to prepare.

Recipe for 1 L of 0.1 M sodium phosphate pH 6.0
ReagentFormulaAmount or action
1 M sodium phosphate dibasic stockprepared aqueous stock12 mLPrepare the defined stock from anhydrous Na2HPO4.
1 M sodium phosphate monobasic stockprepared aqueous stock88 mLPrepare the defined stock from NaH2PO4·H2O (MW 137.99; approximately 137.99 g/L for 1 M).
Purified waterBring the total solution volume to 1 L. Do not add 1 L of water; add water only until the total solution reaches 1 L.
Expected pH: 6.0

Verify the final measured pH experimentally.

How to prepare 0.1 M sodium phosphate pH 6.0

  1. Prepare the 1 M monobasic stock from NaH₂PO₄·H₂O (MW 137.99; approximately 137.99 g/L) and the 1 M dibasic stock from anhydrous Na₂HPO₄, then bring each stock to its final volume.
  2. Measure the scaled volume of each stock for the selected pH preset into a suitable vessel.
  3. Add purified water until the total solution reaches the selected final volume.
  4. Mix thoroughly and verify the final measured pH experimentally at 25 °C.

About This Buffer

Sodium phosphate is a widely used inorganic buffering system in biochemical and biological laboratories. Buffer pH can be established by changing the relative amounts of monobasic and dibasic phosphate. This calculator preserves six fixed 0.1 M formulations at pH 6.0, 6.8, 7.0, 7.2, 7.4, and 8.0 using defined 1 M phosphate stock ratios published for 25 °C rather than interpolating arbitrary pH values.

Common questions

Why does this calculator mix two 1 M phosphate stocks?

Each reviewed pH preset is defined by a fixed ratio of monobasic and dibasic 1 M sodium phosphate stocks at 25 °C.

Can I enter a pH between the listed presets?

No. The page preserves six reviewed stock-mixing ratios and does not interpolate between them.

Why must the phosphate hydration states be specified?

The monobasic stock uses sodium phosphate monobasic monohydrate, NaH₂PO₄·H₂O (MW 137.99; approximately 137.99 g/L for 1 M). The dibasic stock uses anhydrous Na₂HPO₄. These forms must not be interchanged.

Sources and review notes

The source for the currently selected preset appears first. Recipe quantities remain tied to the cited article location.

0.1 M sodium phosphate pH 6.0

Source location: Cold Spring Harbor table — 0.1 M sodium phosphate pH 6.0 from a fixed 1 M stock ratio at 25 °C; registered production formula specifies anhydrous Na2HPO4 and NaH2PO4·H2O stocks, with PMC reproductions retained as cross-checks.

Preparation method: Fixed mixing ratio of defined stock solutions

View sources for all presets

0.1 M sodium phosphate pH 6.8

Source location: Cold Spring Harbor table — 0.1 M sodium phosphate pH 6.8 from a fixed 1 M stock ratio at 25 °C; registered production formula specifies anhydrous Na2HPO4 and NaH2PO4·H2O stocks, with PMC reproductions retained as cross-checks.

Preparation method: Fixed mixing ratio of defined stock solutions

0.1 M sodium phosphate pH 7.0

Source location: Cold Spring Harbor table — 0.1 M sodium phosphate pH 7.0 from a fixed 1 M stock ratio at 25 °C; registered production formula specifies anhydrous Na2HPO4 and NaH2PO4·H2O stocks, with PMC reproductions retained as cross-checks.

Preparation method: Fixed mixing ratio of defined stock solutions

0.1 M sodium phosphate pH 7.2

Source location: Cold Spring Harbor table — 0.1 M sodium phosphate pH 7.2 from a fixed 1 M stock ratio at 25 °C; registered production formula specifies anhydrous Na2HPO4 and NaH2PO4·H2O stocks, with PMC reproductions retained as cross-checks.

Preparation method: Fixed mixing ratio of defined stock solutions

0.1 M sodium phosphate pH 7.4

Source location: Cold Spring Harbor table — 0.1 M sodium phosphate pH 7.4 from a fixed 1 M stock ratio at 25 °C; registered production formula specifies anhydrous Na2HPO4 and NaH2PO4·H2O stocks, with PMC reproductions retained as cross-checks.

Preparation method: Fixed mixing ratio of defined stock solutions

0.1 M sodium phosphate pH 8.0

Source location: Cold Spring Harbor table — 0.1 M sodium phosphate pH 8.0 from a fixed 1 M stock ratio at 25 °C; registered production formula specifies anhydrous Na2HPO4 and NaH2PO4·H2O stocks, with PMC reproductions retained as cross-checks.

Preparation method: Fixed mixing ratio of defined stock solutions

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