Good's buffers

Good's buffers (also Good buffers) are twenty buffering agents for biochemical and biological research selected and described by Norman Good and colleagues during 1966–1980. Most of the buffers were new zwitterionic compounds prepared and tested by Good and coworkers for the first time, though some (MES, ADA, BES, Bicine) were known compounds previously overlooked by biologists. Before Good's work, few hydrogen ion buffers between pH 6 and 8 had been accessible to biologists, and very inappropriate, toxic, reactive and inefficient buffers had often been used. Many Good's buffers became and remain crucial tools in modern biological laboratories.

Selection criteria

Good sought to identify buffering compounds which met several criteria likely to be of value in biological research.

pKa: Because most biological reactions take place near-neutral pH between 6 and 8, ideal buffers would have pKa values in this region to provide maximum buffering capacity there.

Solubility: For ease in handling and because biological systems are in aqueous systems, good solubility in water was required. Low solubility in nonpolar solvents (fats, oils, and organic solvents) was also considered beneficial, as this would tend to prevent the buffer compound from accumulating in nonpolar compartments in biological systems: cell membranes and other cell compartments.

Membrane impermeability: Ideally, a buffer will not readily pass through cell membranes, this will also reduce the accumulation of buffer compound within cells.

Minimal salt effects: Highly ionic buffers may cause problems or complications in some biological systems.