A study on lowering the detection limit with solid-state lead-selective electrodes

The detection limit of a Pb2+ ion-selective electrode with a solid state (PbS/Ag2S) membrane was successfully lowered to the nanomolar range. The electrode was applied in direct potentiometric determination of Pb2+ in aqueous solutions. Hydrodynamics, redox reaction at the solid-state surface as well as time dependency were investigated and found as key factors affecting the low detection limit. By optimizing these parameters improving detection limit by ca. three orders of magnitude was achieved.