A buffer is an aqueous solution that can resist pH changes upon the addition of small amounts of acids and bases. Buffers usually contain a weak acid and its conjugated base or a weak base and its conjugate acid.
The concept of buffer emerged from the observation (Perrin & Dempsey, 1974) that partially neutralized solutions of weak acids or bases resist changes in pH when small amounts of strong acids or bases are added to them.
- Perrin & Dempsey, 1974. Buffers for pH and Metal Ion Control. Chapman & Hall Ltd., London, 161-162.