title: Cobalt speciation study in the cobalt-cysteine system by electrospray ionization mass spectrometry and anion-exchange chromatography inductively coupled plasma atomic emission spectrometry.
abstract: This paper describes the ability of the combination of electrospray ionization mass spectrometry (ESI-MS) and anion-exchange chromatography coupled with inductively coupled plasma atomic emission spectrometry (AEC-ICP-AES) for cobalt speciation study in the binary cobalt-cysteine system. ESI-MS, allowing the identification and the characterization of the analytes, is used as a technique complementary to AEC-ICP-AES, providing elemental information on the separated species. The methods have been developed through the study of samples containing Co2+ and 1-fold to 5-fold molar ratios of cysteine over a pH range 2.5 to 11. In each case, cobalt-cysteine complexes were characterized by ESI-MS in negative ion mode. AEC-ICP-AES allowed further separation and detection of the cobalt species previously characterized. The strong influence of pH and ligand-to-metal ratios on the nature and stoichiometry of the species is demonstrated. For the first time, a direct experimental speciation diagram of cobalt species has been established owing to these analytical techniques. This work is a promising basis for the speciation analysis of cobalt, since a good knowledge of cobalt speciation is of prime importance to better understanding its fate in biological and environmental media.
authors.affiliation: CEA Saclay-DEN/DPC/SECR/LSRM, 91191 Gif sur Yvette, France. bresson@carnac.cea.fr
authors.forename: Carole
authors.initials: C
authors.lastname: Bresson
authors.forename: Christèle
authors.initials: C
authors.lastname: Colin
authors.forename: Frédéric
authors.initials: F
authors.lastname: Chartier
authors.forename: Christophe
authors.initials: C
authors.lastname: Moulin
mesh_terms: D000837:Anion Exchange Resins; D001665:Binding Sites; D002852:Chromatography, Ion Exchange / Q000379:methods*; D003035:Cobalt / Q000032:analysis* / Q000737:chemistry*; D003545:Cysteine / Q000032:analysis* / Q000737:chemistry*; D046911:Macromolecular Substances / Q000032:analysis / Q000737:chemistry; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*; D013054:Spectrophotometry, Atomic / Q000379:methods*
chemical_list: D000837:Anion Exchange Resins; D046911:Macromolecular Substances; D003035:Cobalt; D003545:Cysteine