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Buffer

A buffer solution is a solution containing a conjugate acid-base pair of a weak acid or a weak base.

Buffers are resistant to changes in pH; i.e., buffer components can release or absorb protons in the solution, helping to maintain the pH within certain range.

Example: When acids are added, components of the phosphate buffer absorb the proton, maintaining pH.

When acids are added, buffer components absorb the proton, maintaining pH.

The same buffer can maintain the pH when bases are added.

When bases are added, buffer components release the proton, maintaining pH.

Definitions in the literature

  • Buffers resist a change in pH when protons are produced or consumed. Maximum buffering capacity occurs ± 1 pH unit on either side of pKa. Physiologic buffers include bicarbonate, orthophosphate, and proteins [1].
  • buffer solution: a solution containing a weak acid or base and its salt (the conjugate base or acid) that is resistant to large changes in pH upon addition of strong acids or bases [2].