Determination of formation constants of copper(II) complexes of Adler medium components with a solid-state copper(II) ion-selective electrode.

A general method for the determination of overall conditional formation constants of copper(II) complexes of mycoplasma growth medium (Adler) constituents together with the protonation constants of the complexing ligands was developed. In Adler medium a total of 0.204 +/- 0.004 molar copper binding sites proved to be present with log beta 2 = 8.14 +/- 0.05 (mu = 0.11) and log Ka = 6.14 +/- 0.004. Conditional overall formation constants were calculated at various pH values. Free copper(II) ion concentrations were calculated as a function of the total added amount of copper(II) and pH. The consequences of these findings for the determination of the growth inhibition of mycoplasmas by copper complexes of 2,2'-bipyridyl analogues are stressed.