Direct determination of sub-nanomolar levels of zinc in sea-water by cathodic stripping voltammetry

A novel technique for the determination of nanomolar levels of zinc in aqueous solution is presented. The zinc complex with ammonium pyrrolidine dithiocarbamate is adsorbed on a hanging mercury-drop electrode and the reduction current of zinc is measured by voltammetry. The detection limit for zinc is 3 × 10⁻¹¹M, with 10-min collection time. A procedure is suggested for the simultaneous determination of Ni and Zn in a single sample.