Cyanide ion-selective electrode measurements in the presence of copper

The response of a cyanide ion-selective electrode (ISE) in the presence of copper has been investigated. The interferences of metal ions, like copper, on the response of the cyanide ISE prevents its use for routine direct ana lysis of metal cyanide containing waste water. In this work an improved und erstanding of the chemistry at the electrode, and the effects of different cyanide and copper concentrations and matrix pH values on the electrode res ponse, has been developed. Based on this insight, a semi-empirical approach is described to allow calibration of the ISE enabling the estimation of to tal cyanide. While not as robust as, for example, total cyanide distillatio n, it provides an inexpensive, rapid and convenient approach for more frequ ent and widespread screening of industrial waste waters. (C) 2001 Elsevier Science B.V. All rights reserved.