Quantification of free and metal-complexed cyanide by tetrathionate derivatization

Alexey Kamyshny*, Harry Oduro, James Farquhar

*Corresponding author for this work

    Research output: Contribution to journalArticlepeer-review

    6 Citations (Scopus)

    Abstract

    A sensitive and robust method for detection of free and metal-complexed cyanide in solutions is described. The method does not require a distillation step and is applicable for both low ionic strength and sea-water samples. The method is based on the reaction of cyanide with potassium tetrathionate followed by high-performance liquid chromatography (HPLC) separation and UV detection of formed thiocyanate. The detection limit of the method is 250 nmol L-1 cyanide (6.5 mu g L-1 CN-) without a pre-concentration step. Storage for three days does not significantly change the results. The sum of free and weak metal-complexed cyanide can be measured by tetrathionate derivatization at a pH of 10. The sum of free, weak metal-complexed cyanide, iron(II) and iron(III)-complexed cyanides may be measured by tetrathionate derivatization at pH 4.4. Derivatization requires heating to 90 degrees C for 20 min at pH = 10 and for 12 h at pH = 4.4. Weighted mean recoveries for free, iron(II), iron(III), nickel(II), silver(I), Cd(II) and Zn(II) complexed cyanide were in the range of 87 to 112% and weighted standard deviations were in the range of 1.7 to 10.0%. The method is not applicable for cyanide complexes of gold and cobalt. We illustrate an application of cyanide quantification using pore-waters from the Delaware Great Marsh.

    Original languageEnglish
    Pages (from-to)1506-1517
    Number of pages12
    JournalInternational journal of environmental analytical chemistry
    Volume92
    Issue number13
    DOIs
    Publication statusPublished - 2012

    Keywords

    • cyanide
    • iron-cyanide complexes
    • metallo-cyanide complexes
    • tetrathionate
    • liquid chromatography
    • PERFORMANCE LIQUID-CHROMATOGRAPHY
    • ION-INTERACTION CHROMATOGRAPHY
    • ZERO-VALENT SULFUR
    • SAMPLE PRECONCENTRATION
    • AQUATIC SYSTEMS
    • PROCESS LIQUORS
    • PHASE
    • POLYSULFIDES
    • THIOCYANATE
    • CYANOLYSIS

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