Sulfate-sensing electrodes. The lead-amalgam/lead-sulfate electrode

A new, simplified design and a convenient prepn. procedure for the Pb(Hg)|PbSO4|SO42- electrode are proposed. This procedure ensures prepn. of stable amalgams and reproducible electrode potentials, which make this electrode useful and attractive for both thermodn. studies and electroanal. applications. For these purposes, the electrode prepd. according to the proposed procedure was exhaustively characterized both thermodynamically and as a sulfate-sensing electrode, in different sulfate solns., including H2SO4. Also, a practical standardization procedure is proposed. The Pb(Hg)|PbSO4|SO42- electrode can be structured with a built-in concd. Li2SO4 salt bridge for use as a sulfate-based ref. electrode. This electrode can be operated as a ref. electrode alternative to the conventional calomel or Ag|AgCl ref. electrodes in electroanal. practice.