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Complex Formation in the Region of Metal Hydrolysis and M(OH) 2 Precipitation. A Glass Electrode Potentiometric and Polarographic Study of Cd–(AMPSO) x –(OH) y and Zn–(AMPSO) x –(OH) y Systems
Author(s) -
Machado Carina M. M.,
Cukrowski Ignacy,
Soares Helena M. V. M.
Publication year - 2006
Publication title -
electroanalysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.574
H-Index - 128
eISSN - 1521-4109
pISSN - 1040-0397
DOI - 10.1002/elan.200503458
Subject(s) - potentiometric titration , chemistry , deprotonation , ionic strength , glass electrode , stability constants of complexes , polarography , metal , cadmium , precipitation , electroanalytical method , zinc , hydrolysis , ligand (biochemistry) , inorganic chemistry , analytical chemistry (journal) , electrode , ion , electrochemistry , reference electrode , aqueous solution , chromatography , biochemistry , physics , receptor , organic chemistry , meteorology
The interaction between cadmium or zinc and AMPSO was investigated by DCP and GEP, at fixed total ligand to total metal concentration ratios and various pH values, at 25.0 °C and 0.1 M KNO 3 ionic strength. For Cd–(AMPSO) x –(OH) y system, CdL and CdL(OH) species, were identified, with stability constants values set to (as log β ): 2.1±0.1 and 6.2±0.2, respectively. For Zn–(AMPSO) x –(OH) y system, the proposed final model with stability constants set to (as log β ) is: ZnL=2.5±0.1 and ZnL(OH) 2 =12.9±0.2. For both systems, the fact that AMPSO deprotonation occurs in the metal hydrolysis and M(OH) 2 precipitation and the complexes formed are not too strong added a real challenge to data interpretation.