ASTM: D2036A: Cyanides, Total, after Distillation (Test Method A)
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Official Method Name
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Standard Test Methods for Cyanides in Water |
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Current Revision
| 1998 |
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Media
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WATER |
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Instrumentation
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Spectroscopy (Colorimetry; Photometry) |
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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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Brief Method Summary
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Test Method A, Total Cyanides, is based on the decomposition of nearly all cyanides in the presence of strong acid, magnesium chloride catalyst, and heat during a 1-h reflux distillation. |
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Scope and Application
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This test method covers the determination of cyanides in water, including the iron cyanide complexes (total cyanide). The cyanide in some cyano complexes of transition metals, for example, cobalt, gold, platinum, etc., is not determined. Either the titration, colorimetric or selective ion electrode procedure can be used to quantify the cyanide concentration. This test method has been used successfully on reagent and surface water and coke plant, refinery, and sanitary waste waters. |
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Applicable Concentration Range
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colorimetric 0.03 - 1.0 mg/L; titration 1.0 - 5.0 mg/L; and selective ion electrode 0.03 - 1.0 mg/L |
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Interferences
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Common interferences in the analysis for cyanide include oxidizing agents, sulfides, aldehydes, glucose and other sugars, high concentration of carbonate, fatty acids, thiocyanate, and other sulfur containing compounds. The method provides for elimination of specific interferences. |
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Quality Control Requirements
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The method provides for verification of systems for quantifying cyanide in the distillate; verification of the distillation procedure; demonstration of analyst proficiency; and demonstration of laboratory proficiency. |
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Sample Handling
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Collect the sample in accordance with Practices D 3370. Minimize exposure of samples to ultraviolet radiation that causes photodecomposition of some metal cyanide complexes and may significantly increase the concentration of free cyanide in the sample. If the sample cannot be analyzed immediately, stabilize it by the addition of sodium hydroxide (NaOH) pellets to a pH of 12 to 12.5 and store it in a closed bottle (dark bottle if available) in a dark and cool environment. |
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Maximum Holding Time
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Relative Cost
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Less than $50 |
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Sample Preparation Methods
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