title: Voltammetry assisted by multivariate analysis as a tool for speciation of metallothioneins: competitive complexation of alpha- and beta-metallothionein domains with cadmium and zinc.
abstract: Multivariate Curve Resolution by Alternating Least Squares (MCR-ALS) is applied to voltammetric data obtained in the study of competitive complexation of Zn(II) and Cd(II) by alpha- and beta-domains of metallothionein (MT). The application of MCR-ALS allows the estimation of both the voltammograms and the concentration profiles associated with each electrochemical process. The complexity of the voltammograms obtained in titrations of the alpha- or beta-domains of MT with Cd(II) and later Zn(II) (or vice versa) prevents their direct interpretation using traditional electrochemical methods. But when MCR-ALS is applied, voltammograms can be interpreted rather satisfactorily in both qualitative and quantitative terms. MCR-ALS showed the formation of Cd2Znbeta dom and Cd3Znalpha dom complexes when both metals were competitively added. A method based on the combined use of voltammetry and some chemometric techniques is proposed. It can be useful for the metal speciation of environmentally relevant natural ligands.
authors.affiliation: Departament de Química Analítica, Facultat de Química, Universitat de Barcelona, Av. Diagonal 647, E-08028 Barcelona, Spain.
authors.forename: María José
authors.initials: MJ
authors.lastname: López
authors.forename: Cristina
authors.initials: C
authors.lastname: Ariño
authors.forename: Silvia
authors.initials: S
authors.lastname: Díaz-Cruz
authors.forename: José Manuel
authors.initials: JM
authors.lastname: Díaz-Cruz
authors.forename: Roman
authors.initials: R
authors.lastname: Tauler
authors.forename: Miquel
authors.initials: M
authors.lastname: Esteban
mesh_terms: D002104:Cadmium / Q000737:chemistry*; D004563:Electrochemistry; D004784:Environmental Monitoring / Q000379:methods; D004785:Environmental Pollutants / Q000032:analysis*; D008024:Ligands; D008668:Metallothionein / Q000032:analysis / Q000737:chemistry*; D015999:Multivariate Analysis; D015032:Zinc / Q000737:chemistry*
chemical_list: D004785:Environmental Pollutants; D008024:Ligands; D002104:Cadmium; D008668:Metallothionein; D015032:Zinc