Selectrode--the universal ion-selective electrode-V. Complex formation studies with the Cu(II) Selectrode.
The Cu(II) Selectrode, calibrated in a series of Cu(II) buffers at various pH levels, has been used for the determination of the stability constants of the Cu(II) complexes of glycine and EGTA at an ionic strength of 0.1. Methods for the calculation of the stability constants of chelate complexes from pH and pM values are presented. The values obtained compare very favourably with those recorded in the literature. For the Cu(II)-EGTA system, for which only a few stability constants have been determined, the following constants were found: logK(Cu, L)(CuL) = 16.80; logK(H, CuL)(CuHL) = 5.30; logK(2H, CuL)(CuH2L) = 7.64; logK(H, CuHL)(CuH2L) = 2.34; logK(Cu, HL)(CuHL) = 12.56; and logK(Cu, H2L)(CuH2L) = 5.97. Examples of the application of the Cu(II) Selectrode in replacement reactions are illustrated.
Hansen
E H
EH
Chemistry Department A, The Technical University of Denmark, Building 207, 2800 Lyngby, Denmark.
Ruzicka
J
J