The determination of small amounts of cyanide in the presence of ferrocyanide by distillation under reduced pressure

Abstract

In the analysis of effluents and waters, the customary use of lead acetate to prevent the decomposition of ferrocyanide during the distillation of cyanide is not sufficiently effective when small concentrations of cyanide (about 0·1 mg 1^–1) are to be determined. A method is described in which the decomposition of ferrocyanide can be completely prevented by distilling off the cyanide under reduced pressure in the presence of zinc acetate. The cyanide in the distillate is determined by the pyridine-pyrazolone method.