| Abstract: | Abstract Cyanide can be measured in the presence of dithionite and its decomposition products by the method of Liebig-Deniges after treatment of the sample with excess iodine, followed by sulfite. The iodine oxidizes dithionite, sulfite and thiosulfate to sulfate at pH 10. Any cyanide present in the sample will form iodine cyanide. Sulfite reduces excess iodine to iodide and converts cyanogen iodide to iodide and cyanide. A large amount of iodide in the sample shifts the end point of the titration significantly. An appropriate blank must be carried through the procedure to correct for the excess iodide. |
