Amperometric determination of cyanide by use of a flow-through electrode

A new approach to cyanide determination based on the measurement of the diffusion current arising from the oxidation of silver to dicyanoargentate(I) is described. Parameters defining the effect of the electrode geometry and the hydrodynamic characteristics of the system on the response of the electrode have been evaluated so that the performance can be optimized. Response is fast and linear for levels from one microgram to several grams per litre of solution. By use of the flow injection principle and a manifold arrangement, absolute amounts of less than one nanogram of cyanide can be determined precisely in volumes as small as 10 mul and at a rate exceeding 100 samples per hour. The method is easily adapted to automated routine analytical control and continuous monitoring of industrial processes depending on the use of cyanide, such as galvanizing plants and certain organic synthetic industries, and also to control of effluents.