BEST — A new program for rigorous calculation of equilibrium parameters of complex multicomponent systems

Abstract

The FORTRAN program BEST for the refinement of stability constants from potentiometric data measured on complex systems containing any number of interacting components is described. The core algorithm consists of computation by successive approximations of the pH values at each equilibrium point from an initial set of stability constants based on the equilibrium model. Each approximation results in adjustment of the equilibrium constants being refined in order to improve the fit between the calculated and observed pH values for all the data taken for the system under investigation. Novel features of the algorithm include total generality, minimization of errors with respect to pH, and the avoidance of customary classification labels such as "metal ion", "ligand", "hydroxides", "proton", etc. Several examples of applications to real systems are provided to illustrate the versatility of the program.