MAXC Computer Program for Calculating Free Ca²⁺ Concentrations—Note 19.2

In solutions that contain several chelating species, or that contain ions such as Zn²⁺ that compete with Ca²⁺for binding to BAPTA or EGTA, calculating the free Ca²⁺ concentration requires simultaneously solving multiple equilibrium expressions. Except for the simplest cases where analytical solutions are feasible, researchers must use an iterative computer program to complete these calculations. MAXCHELATOR, a series of programs for determining free metal concentrations in the presence of chelators, is freely accessible on the Web.