Speciation analysis of nickel in the latex of a hyperaccumulating tree Sebertia acuminata by HPLC and CZE with ICP MS and electrospray MS-MS detection
Résumé
Speciation of nickel was investigated in a hyperaccumulator tree, Sebertia acuminata, by liquid chromatography (LC) with parallel ICP MS and electrospray MS-MS detection. The latex of the tree was leached with water. Two separation mechanisms, size-exclusion (SEC) and capillary zone electrophoresis (CZE), were investigated for the separation of Ni-complexes. A preparative scale SEC allowed the isolation of six stable nickel species. A nickel complex with Mr 360 was identified by ES MS. The collision induced fragmentation (CID) of the mlz 360 ion suggested the presence of three carboxylic and one amino groups, and allowed the identification of a Ni-complex with nicotianamine. A modification of the SEC column with Ni2+ ions allowed the isolation of a fraction containing nickel citrate. Quantification of the species showed that in the water extract of the latex 99.4% of the nickel is complexed by citrate and 0.3% by nicotianamine. © The Royal Society of Chemistry 2003.