Competitive binding of cadmium by plant thiols: an electrochemical study assisted by multivariate curve resolution.
Multivariate curve resolution with alternating least squares (MCR-ALS) has been applied to voltammetric data obtained from analysis of the competitive binding of cysteine (Cys) and cysteine-glycine (Cys-Gly) by Cd(II) as a first approach towards mixtures of phytochelatins and related compounds in natural media. From different starting points, the possibilities of formation of mixed complexes and/or displacements between ligands are investigated. Analysis of the resulting unitary voltammograms and concentration profiles of the resolved components by MCR-ALS suggests that the strongest ligand (Cys-Gly) is able to displace the weakest (Cys) from its metal complexes, whereas this does not happen in the opposite direction. On the other hand, no evidence of Cd mixed-ligand complexes was found.
Gusmão
Rui
R
Departament de Química Analítica, Universitat de Barcelona, Martí i Franquès 1-11, 08028, Barcelona, Spain.
Ariño
Cristina
C
Díaz-Cruz
José Manuel
JM
Esteban
Miquel
M
D001667:Binding, Competitive; D002104:Cadmium / Q000737:chemistry*; D003545:Cysteine / Q000737:chemistry; D004563:Electrochemistry; D005998:Glycine / Q000737:chemistry; D016018:Least-Squares Analysis; D015999:Multivariate Analysis; D010944:Plants / Q000737:chemistry*; D013438:Sulfhydryl Compounds / Q000737:chemistry*
D013438:Sulfhydryl Compounds; D002104:Cadmium; D003545:Cysteine; D005998:Glycine