1.0 SCOPE AND APPLICATION

1.1 This method covers the determination of cyanide in drinking, ground, surface, and saline waters, domestic and industrial wastes. 1.2 The applicable range is 5 to500 µg/L. 2.0 SUMMARY OF METHOD 2.1 The cyanide as hydrocyanic acid (HCN) is released from cyanide complexes by means of a manual reflux-distillation operation and absorbed in a scrubber containing sodium hydroxide solution. The cyanide ion in the absorbing solution is converted to cyanogen chloride by reactions with chloramine-T, that subsequently reacts with pyridine and barbituric acid to give a red-colored complex. 2.2 Reduced volume versions of this method that use the same reagents and molar ratios are acceptable provided they meet the quality control and performance requirements stated in the method. 2.2 Limited performance-based method modifications may be acceptable provided they are fully documented and meet or exceed requirements expressed i