Reversed-phase HPLC of diethyldithiocarbamate complexes using radial compression columns

The diethyldithiocarbamate complexes of Co(III), Cr(III), Cu(II), Hg(II), Ni(II), Pb(II), Se(IV) and Te(IV) are separable on a Waters Assoc. Radial Pak C18 column using a mobile phase of methanol-acetonitrile-water (40:35:25), provided the column has been conditioned by prior injection of a concentrated mixture of the complexes. Alternatively, the column can be conditioned by flushing with 0.005 M disodium ethylenediamine tetraacetate (EDTA), with subsequent addition of 1.2510-5 M EDTA to the mobile phase. Diethyldithiocarbamate complexes of Pb(II), Cd(II) and Fe(III) gave poor peak shape due to substitution reactions with nickel from stainless steel components of the chromatographic system. The analysis of a synthetic electroplating solution containing salicylsulphonic acid, sulphanilamide and six inorganic ions is illustrated.