Liquid chromatography of metal chelates. Chromatographic studies of homologous dialkyldithiocarbamates

The chromatographic behaviour of a selected group of metal dithiocarbamates was investigated by reversed-phase, liquid chromatography, Ligands with th e general formula R2NCSSNa, where R is CH3CH2-, CH3CH2CH2-, (CH3)(2)CH-, CH 3CH2CH2CH2- or CH3CH2CH2CH2CH2- were synthesised and used to prepare the co rresponding complexes of zinc(II), arsenic(III), iron(III), cadmium(II), le ad(II), nickel(II), copper(II), mercury(II), cobalt(III) and chromium(III). The chromatographic behaviour of the metal complexes on a C-18 column was examined with the mobile phases comprising methanol-water, acetonitrile-wat er and methanol-acetonitrile-water. With the exception of one ligand [where R=(CH3)(2)CH-], the majority of the chelates were resolved satisfactorily. Although the Cd(IT) and Pb(II) comp lexes were not resolved by the binary solvent systems, those derived from t he straight-chain, higher homologues (C-3-C-5) were successfully separated with ternary solvent mixtures. Chelates of Zn(II), Fe(III) and the diethyldithiocarbamate of As(LII) were not observed using any of these mobile phases. (C) 1999 Elsevier Science B. V. All rights reserved.