The determination of cyanide is very important not only in electroplating baths and when decontaminating wastewater but, due to its high toxicity, also in water samples in general. Concentrations of 0.05 mg/L CN- can already be lethal for fish.
This Bulletin describes the determination of cyanide in samples of different concentrations by potentiometric titration.
Chemical reactions:
2 CN- + Ag+ → [Ag(CN)2]-
[Ag(CN)2]- + Ag+ → 2 AgCN