The operation of the cyanide-sensitive Mintek/TB1 kegold electrode was
studied in the laboratory, with regard to equilibration time and drift, the
effects of pH, stirring, salinity, dissolved oxygen, zinc and copper(I) ions.
Methods for valid calibration in the range 20-600 mg(NaCN)/L and pH
values in the range 9 - 12 in the absence of copper were also studied.
Increasing the salinity beyond a threshold of 40 g(NaCI)/L improves
calibration and measurement. The sensitivity is 91 mV per decade change
in the concentration of ionic cyanide, and output is reproducible to within
10 mV with attention to the factors listed above. However, salinity of 40
g(NaCI)/L also sensitises the electrode to interference by copper(1) ions.
This copper sensitivity seems capable of saturation, suggesting a research
strategy for possible remedies.