O-I-Analytical: OIA-1677: Cyanide by Amperometry
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Official Method Name
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Available Cyanide by Flow Injection, Ligand Exchange, and Amperometry |
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Current Revision
| Aug-99 |
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Media
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WATER |
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Instrumentation
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Amperometer |
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Method Subcategory
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Inorganic |
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Method Source
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Citation
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This method is available from OI Analytical, P.O. Box 9010, College Station, TX 77842-9010 (http://www.oico.com). For Method OIA-1677, you can also see http://www.epa.gov/waterscience/methods/cyanide/ for a copy of OIA-1677 or information on its approval for wastewater compliance monitoring. |
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Brief Method Summary
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The analytical procedure employed for determination of available cyanide is divided into two parts: sample pretreatment and cyanide detection. In the pretreatment step, proprietary ligand-exchange reagents are added at room temperature to 100 mL of a cyanide-containing sample. The ligand-exchange reagents displace cyanide ion from transition metal ions that exist as available cyanide complexes, resulting in the release of cyanide ion (free cyanide). The sample containing free cyanide is analyzed using a flow-injection analysis (FIA) system. The addition of hydrochloric acid in the FIA system converts cyanide ion to hydrogen cyanide (HCN) that passes under a gas diffusion membrane. The HCN diffuses through the membrane into an alkaline receiving solution where it is converted back to cyanide ion. The cyanide ion is monitored amperometrically with a silver working electrode, silver/silver chloride reference electrode, and platinum/stainless steel counter electrode, at an applied potential of zero volt. The current generated is proportional to the cyanide concentration present in the original sample. Total analysis time is approximately two minutes. |
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Scope and Application
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This method determines available cyanide in water and wastewater in other waters. |
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Applicable Concentration Range
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2.0 ug/L to 5.0 mg/L |
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Interferences
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Keep all glassware and other items free of contaminants. Method documentation covers steps to treat samples containing sulfide, aldehydes, oxidizing agents, high carbonate concentrations, and large amounts of colloids. |
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Quality Control Requirements
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Each laboratory that uses this method is required to operate a formal quality assurance program. The minimum requirements of this program consist of an initial demonstration of laboratory capability, and the periodic analysis of LCSs and MS/MSDs as a continuing check on performance. Laboratory performance is compared to established performance criteria to determine if the results of the analyses meet the performance characteristics of the method. |
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Sample Handling
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Collect samples in amber glass bottles with PTFE-lined caps. Preserve sample following preservation techniques in method, followed by pH adjustment to less than 12. Refrigerate immediately. |
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Maximum Holding Time
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Preserved samples: 14 days. Unpreserved samples: less than 24 hours. |
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Relative Cost
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$51 to $200 |
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Sample Preparation Methods
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