Comparative study of different cyanide-selective air-gap electrodes

The characteristics of four solid-state cyanide-selective air-gap electrodes are described. When a minute volume of dicyanoargentate(I) solution was used as electrolyte, the double-Nernstian response to cyanide concentration was obtained only with the sensors based on silver or silver sulphide. Sensors based on silver iodide or a silver sulphide/iodide mixture displayed the normal Nernstian character shown by cyanide-selective electrodes dipped in solution. A theoretical explanation of the results involves the relevant equilibrium equations and the mass balance.