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Heterogeneity of Cd(II)‐Macromolecule Systems: A Potentiometric Study
Author(s) -
Serra Roger,
Mas Francesc,
DíazCruz José Manuel,
Ariño Cristina,
Esteban Miquel
Publication year - 2000
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/(sici)1521-4109(20000101)12:1<60::aid-elan60>3.0.co;2-o
Subject(s) - potentiometric titration , ionic strength , chemistry , scatchard plot , stability constants of complexes , macromolecule , homogeneous , humic acid , ionic bonding , electroanalytical method , inorganic chemistry , thermodynamics , ion , binding site , biochemistry , organic chemistry , aqueous solution , electrode , fertilizer , physics
The complexation of Cd(II) with polymethacrylic acid (PMA) and humic acid (HA) has been studied potentiometrically with a Cd‐ISE at constant pH and ionic strength. Experimental data have been analyzed qualitatively by means of Scatchard plots to see the heterogeneity of the system and to predict the number of different functional groups. A quantitative description of the complexation behavior has been given by fitting the binding curves to a Freundlich isotherm which provides a global characterization of the complexation process. The results obtained suggest an homogeneous behavior for the Cd(II)‐PMA system and an heterogeneous one for the Cd(II)‐HA system. Conditional intrinsic stability constants have been obtained for both systems.