NEMI Method Summary

Method Summary Information

Method Number: I-1300 Media: WATER
Revision: 1985
Method Source: U.S. Geological Survey (USGS)
Subcategory: INORGANIC Analytes in this method
Official Name: Dissolved Cyanide in Water by Colorimetry with Pyridine-Pyrazolone
Descriptive Name Cyanide, dissolved in Water by Colorimetry
Source Info: USGS Branch of Information Services
Box 25286, MS 417
Federal Center
Denver, CO 80225-0286
Phone: 303-202-4700
Citation: USGS Methods, Volume A1
113060 Byte file
Brief Method
Summary:
 Assemble a distillation train. Add 400 mL of water or water-suspended sediment to the boiling flask. Add 50 mL of 1M NaOH and 100 mL of demineralized water to the gas washer. Adjust suction to 2 bubbles per second. Add 10 mL of MgCl2 solution through the thistle tube. Let the airflow mix for 3 min. Add 20 mL of concentrated H2SO4. Apply heat for a rapid boil. Reflux for 1 hour. Let the airflow continue for another 15 min. Dilute the transferred gas washer contents to 200 mL. Add NaOH and demineralized water to the gas washer. Repeat the reflux procedure. Prepare a blank by adding 15 mL of 0.25 M NaOH into a 23-mm absorption cell fitted with a rubber stopper. Prepare standards containing 0.0005 mg and 0.001 mg of cyanide. Adjust the volume of each to 15 mL using 0.25 M NaOH. Place 15 mL aliquots of the distillates in 23-mm stoppered absorption cells. Neutralize each sample, blank, and standard with 3 M HC2H3O2 using phenolphthalein indicator solution. Add 4 drops of chloramine-T solution to each sample, blank, and standard. Shake for 2 min. Add 5 mL pyridine-pyrazolone reagent and mix. Let stand for 20 min for color development. Read absorbances at 620 nm. The color is stable for 30 min.
Scope And
Application:
 This method is applicable to water and water-suspended sediment containing at least 0.01 mg/L of cyanide.
Applicable
Conc Range:
 0.2 - 1000mg/L
Interferences: Common interferences include sulfide, heavy-metal ions, fatty acids, steam-distillable organic compounds, cyanate, thiocyanate, glycine, urea, oxidizing agents, and substances that may contribute color or turbidity to the sample.
QC Requirements: Not Included
Sample Handling: No information given.
Max Holding Time:
 
Relative Cost: Less than $50
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