Free-metal ion depletion by "Good's" buffers.

Metal-ion affinity (formation) constants were determined for two "Good's" buffers, N-tris(hydroxymethyl)methyl-2-aminoethanesulfonic acid (TES) and N,N-bis(2-hydroxyethyl)glycine (bicine). The metal chelates formed undergo loss of an internal ligand (alcohol) proton (bicine) and undergo hydrolysis (bicine and TES) and dimerization reactions (TES). Bicine and TES buffer not only hydrogen ions but also metal ions. The metal complexes of "Good's" buffers also buffer hydrogen ions by secondary reactions. The consequences of these reactions are considered in relation to biomedical research.