1.1 ,This test method is used for determining total cyanide in drinking and surface waters, as well as domestic and industrial wastes. Cyanide ion (CN^–,), hydrogen cyanide in water (HCN(aq)), and the cyano-complexes of zinc, copper, cadmium, mercury, nickel, silver, and iron may be determined by this test method. Cyanide ions from Au(I), Co(III), Pd(II), and Ru(II) complexes are only partially determined.