摘要：In the determination of total cyanide ions in water, which are liberated by the distillation of the sample in the presence of ethylenediamine tetraacetic acid (EDTA), it is not yet clarified whether the addition of EDTA is effective or not for the liberation of free cyanide ion from the metal cyanide complexes. It was found that, without the help of EDTA, free cyanide ion was liberated almost quantitatively from most of metal complexes belonging to group A except three metal complexes, K4Fe (CN)6+Zn2+, K4Fe (CN)6+Cu2+, and K3Fe (CN)6+Cu2+. Liberation of cyanide ion from these three metal complexes was not quantitative in the absence of EDTA, but was quantitative in the presence of EDTA. From these facts, the addition of EDTA is recommended for the determination of total cyanide ions in waste water.
