Studies on an araldite‐based membrane of copper hexacyanoferrate (III) as a caesium ion‐sensitive electrode

Solid membranes of copper hexacyanoferrate (III) in araldite are evaluated as a caesium ion‐sensitive electrode. The electrode can be used for caesium determination in the concentration range of 10 −1 to 10‐ 4 M . The potentials generated across the membrane are reproducible and steady potentials are attained in about 1 to 2min. The same electrode can be used over a period of 6 months without significant change in potential. The electrode can be used in the pH ranges 2.5–6.0 at 10 −2 M Cs + and 3.0–6.0 at 10 −3 M CS + , and in presence of a number of interfering ions. Potentiometric titration of caesium nitrate with 12‐moIybdophosphoric acid was also carried out using the membrane as an end point indicator.