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Selectivity coefficients for methods for reporting Kab values
Pure Appl. Chem., 67 (3): 507-518 (1995)
Аннотация
The limitations of the Nicolsky-Eisenman (N-E) equation for the determination of potentiometric selectivity coefficients, Kab , were critically evaluated in terms of K G values for ions of unequal charge, non-Nernstian behavior of interfering ions, and activity dependence of Kab. The reasons for the activity dependence of Kab and for non-equalities of values depending on the method employed were thus elucidated. Also, when ions of different charge were involved, Kab values obtained were found to be either unrealistically large or small depending on whether the ion of higher charge was considered as a primary or an interfering ion. On the basis of these considerations, new approaches including the matched potential method, a method independent of the N-E equation, were recommended for the determination of Kab.
