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Relationship of multidimensional predominance-zone diagrams with multiconditional constants for complexation equilibria

1991; Elsevier BV; Volume: 246; Issue: 2 Linguagem: Inglês

10.1016/s0003-2670(00)80983-6

1873-4324

Alberto Rojas-Hernándéz, M. T. Ramírez, Jorge G. Ibáñez, Ignacio González,

Analytical Chemistry and Sensors

A generalized method for the construction of predominance-zone diagrams using conditional constants is presented. This generalization permits the construction of multidimensional diagrams using multiconditional constants for the study of chemical equilibria in aqueous solutions of multicomponent systems. The predominance-zone diagrams can be constructed by defining generalized species, complexation coefficients (with a multiplicative structure instead of the traditionally used additive structure) and generalized complexation and dismutation equilibria for multibuffered systems. Systems involving mixed complex formation were studied by using copper(II)-nitrilotriacetic acid-histidine-proton (under buffered conditions in pHist′ and pH) and mercury(II)-ethylenediaminetetraacetic acid-ammonia-proton (under buffered conditions in pNH3′ and pH) as examples.