Pneumatopotentiometric determination of nanogram amounts of cyanide

✍ Scribed by František Opekar

• Publisher: Elsevier Science
• Year: 1986
• Tongue: English
• Weight: 453 KB
• Volume: 183
• Category: Article
• ISSN: 0003-2670
• DOI: 10.1016/0003-2670(86)80100-3

✦ Synopsis

Hydrogen cyanide is liberated from aqueous samples by reaction with sulphuric acid and transferred by a stream of nitrogen to a silver porous membrane electrode. Some HCN passes through the membrane into an alkaline dicyanoargentate solution; the cyanide ion produced causes a decrease in the equilibrium Ag+ concentration and the change of potential is related to the amount of cyanide in the sample. The detection limit is 3.0 ng ml-' cyanide in the injected solution; the relative standard deviation is 0.82% for 17 ng of cyanide. Sulphide interferes (as H,S) but can be removed on a lead acetate column.