Amperometric detection of unithiol complexes of heavy metals in high-performance liquid chromatography

It was demonstrated that Pb(II), Cd(II), Hg(II), Ni(II), Co(II), and Cu(II) can be indirectly determined as their unithiol complexes by amperometric d etection under static and HPLC conditions. Factors affecting the chromatogr aphic separation and amperometric detection of metal complexes of unithiol were studied. Two designs of flow electrochemical cells (thin-layer and wal l-jet cells) and three electrode materials (platinum, graphite, and glassy carbon) were compared. The best sensitivity was attained for an amperometri c detector with. wall-jet flow cell and a graphite indicator electrode. The detection limits for Hg(II), Pb(II), and Cd(II) were 0.9, 0.3, and 0.1 mu g/mL, respectively. The chromatographic determination of heavy metals in a sample of waste water was carried out using the amperometric detector.