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Binding of Cd 2+ and Zn 2+ with the Phytochelatin (γ‐Glu‐Cys) 4 ‐Gly: A Voltammetric Study Assisted by Multivariate Curve Resolution and Electrospray Ionization Mass Spectrometry
Author(s) -
Chekmeneva Elena,
DíazCruz José Manuel,
Ariño Cristina,
Esteban Miquel
Publication year - 2007
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.200603733
Subject(s) - chemistry , electrospray ionization , stoichiometry , mass spectrometry , titration , analytical chemistry (journal) , polarography , electrospray , crystallography , inorganic chemistry , chromatography
The complexation of Cd 2+ and Zn 2+ with the phytochelatin (γ‐Glu‐Cys) 4 ‐Gly (PC 4 ) is studied by Differential Pulse Polarography (DPP) assisted by Multivariate Curve Resolution with Alternating Least Squares (MCR‐ALS) and by Electrospray Ionization Mass Spectrometry (ESI‐MS). In the case of Zn 2+ , voltammetric results show the presence of an inert electroinactive Zn 2+ PC 4 complex, which is confirmed by ESI‐MS. In the case of Cd 2+ , the unitary DPP peaks and the concentration profiles obtained by MCR‐ALS from DPP titrations of PC 4 with Cd 2+ suggest the formation of two electroactive Cd 2+ PC 4 complexes. The first complex, with a 1 : 1 stoichiometry, shows a fixed DPP peak potential characteristic of a kinetically inert behavior. After further Cd 2+ additions a second labile complex seems to be formed. This behavior is confirmed by ESI‐MS detection of CdPC 4 and Cd 2 PC 4 complexes.