ELECTROCHEMICAL AND X-RAY-INVESTIGATIONS ON THE SYSTEM (CU,HG,ZN) WITH REGARD TO THE CU-ZN INTERFERENCE

EMF and CV measurements on ternary amalgams (Cu,Hg,Zn) were performed with Cu and Zn contents varying over a wide range, even above saturati on. It was shown that the known interference between Cu and Zn in anal ytical chemistry is caused by an intermetallic compound, whose formati on from gamma-CuHg and Zn is slow compared with the electrode kinetics of Zn and Cu af Hg. Its electrode potential is similar to 150 mV more postive than the Zn potential. The diffractogram of this phase leads to the conclusion that the intermetallic compound is the beta-phase '' CuZn'' distributed as nanocrystallites in Hg. Nanocrystallinity of ''C uHg'' is a prior condition for the interference to occur. (C) 1998 Els evier Science Ltd. All rights reserved.