Indirect determination of cyanide ion and hydrogen cyanide by adsorptive stripping voltammetry at a mercury electrode

Abstract

An indirect voltammetric method is described for determination of cyanide ions and hydrogen cyanide, using the effect of cyanide on cathodic adsorptive stripping peak height of Cu–adenine. The method is based on competitive Cu complex formation reaction between adenine at the electrode surface and CN − ions in solution. Under the optimum experimental conditions (pH=6.42 Britton–Robinson buffer, 1×10 −4 M copper and 8×10 −7 M adenine), the linear decrease of the peak current of Cu–adenine was observed, when the cyanide concentration was increased from 5×10 −8 to 8×10 −7 M. The detection limit was obtained as 1×10 −8 M for 60 s accumulation time. The relative standard deviations for six measurements were 4 and 2% for the cyanide concentrations of 5×10 −8 and 2×10 −7 M, respectively. The method was applied to the determination of cyanide in various industrial waste waters such as electroplating waste water and also for determination of hydrogen cyanide in air samples.