STRIPPING CHRONOPOTENTIOMETRY OF IMMOBILIZED MICROPARTICLES

Stripping chronopotentiometric measurements following the mechanical t ransfer of insoluble solid reactants to the surface of a paraffin impr egnated graphite electrode are described. By the new technique, the po tentials can be determined at which the heterogeneous redox reactions between the immobilized microcrystals and dissolved oxidants, or reduc tants occur. The method is tested with lead and tin metal particles an d lead(II)oxide and sulfide powders in the oxygen saturated electrolyt es of various pH. The oxidation of lead is a fast process, but tin par ticles are highly passivated in the basic media. A difference between the responses of electrodeposited and mechanically transferred lead is reported. (C) 1998 Elsevier S.A. All rights reserved.