Voltammetric determination of heavy metals leached from ceramics

Anodic stripping voltammetry using a mercury film electrode (MFE) and hanging mercury drop electrode (HMDE) was applied for the determination of trace amounts of lead, cadmium, zinc and copper leached from plates by 4% acetic acid standard solution. The use of a MFE, the fast scan rate (1000 mV/s) by DC voltammetry with subtraction of background current allowed to determine low concentrations of heavy metals. The amounts of metals leached from ware were Pb: 0.1 to 25, Cd: 0.015 to 0.44, Zn: 0.07 to 1.06, Cu: 0.14 to 0.40 μg/mL, depending on the kind of plate and manufacture. Determinations of copper and zinc were carried out using the HMDE electrode in the leachate, determination of tin after medium exchange, and thallium after complexing of lead by EDTA. A significant decrease of metals leached during the second leaching and after washing with detergent solution was found for plates with overglaze decoration. Received: 5 November 1997 / Revised: 24 February 1998 / Accepted: 26 February 1998