USGS-NWQL: I-4302: Cyanide, whole water recoverable; colorimetric
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Official Method Name
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Cyanide, colorimetric, barbituric acid, automated-segmented flow |
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Current Revision
| 1985 |
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Media
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WATER |
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Instrumentation
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Automated Spectrophotometer |
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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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Methods for the Determination of Inorganic Substances in Water and Fluvial Sediments, Techniques of Water-Resources Investigations of the United States Geological Survey, Book 5, Chapter A1 Edited by Marvin J. Fishman and Linda C. Friedman |
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Brief Method Summary
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This method is based on the chlorination of cyanide with chloramine-T and on the subsequent reaction with a pyridine-barbituric acid reagent (Goulden and others, 1972). This method detects simple cyanides only; therefore, any complex cyanides must first be broken down by passing the acidified sample solution through an ultraviolet digestion-distillation procedure. The distillation step also removes certain interferences. |
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Scope and Application
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This method may be used to analyze water-suspended sediment containing from 0.01 to 0.30 mg/L cyanide. Samples containing more than 0.30 mg/L need to be diluted. Total recoverable cyanide in water-suspended sediment can be determined if each sample is shaken vigorously and a suitable aliquot of well-mixed sample withdrawn. |
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Applicable Concentration Range
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0.010 - 0.30 mg/L |
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Interferences
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Chloride interferes if its concentration exceeds 3,000 mg/L. Oxidizing agents may interfere. Glycine and urea at the 10-mg/L level do not interfere. A concentration of 10 mg/L sulfide increases the apparent cyanide concentration by approx 0.02 mg/L. Concentrations of sulfide greater than 10 mg/L interfere considerably. Thiocyanate is broken down to cyanide and sulfide by this procedure and, therefore, interferes on an equimolar basis. Sulfate concentrations of 4,000 mg/L do not interfere. Higher concentrations were not tested. |
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Quality Control Requirements
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Calibrate instrument using calibration standards (CAL). Quality control samples (QCS) and laboratory blanks (LB) analyzed at a minimum of I each after every 10 samples |
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Sample Handling
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Container Description: 250 mL Polyethylene bottle Treatment and Preservation: Use unfiltered sample to rinse bottles; then adjust pH of collected sample to >12 with NaOH; chill and maintain at 4 deg C; ship immediately. |
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Maximum Holding Time
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180 days |
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Relative Cost
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Less than $50 |
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Sample Preparation Methods
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