NEMI Method Summary


Method Summary Information

Method Number:

335.3

Media:

WATER

Revision:

Issued 1978

Method Source:

U.S. EPA National Exposure Research Laboratory (NERL) [formerly EMSL]

Analytes in this method

Subcategory:

INORGANIC

Official Name:

Cyanide, Total (Colorimetric, Automated UV)

Descriptive Name

Cyanide by Automated Colorimetry

Source Info:

U.S.EPA National Exposure Research Laboratory (NERL)
Microbiological and Chemical Exposure Assessment Research Division (MCEARD)
[formerly the Environmental Monitoring Systems Laboratory (EMSL), Cincinnati, OH]
26 West Martin Luther King Drive
Cincinnati, Ohio 45268-0001
Fax: 513-569-7757
email: DWmethods.help@epa.gov

Citation:

Methods for the Chemical Analysis of Water and Wastes (MCAWW) (EPA/600/4-79/020)

37078

Byte file

Brief Method
Summary:

Cyanide, as HCN, is released from cyanide complexes by means of UV digestion and distillation. Cyanides are converted to cyanogen chloride by reactions with chloramine-T which subsequently reacts with pyridine and barbituric acid to give a red-colored complex that is measured with an on-line colorimeter.

Scope And
Application:

The automated method determines cyanide in drinking and surface waters; domestic and industrial wastes.

Applicable
Conc Range:

0.005 - 0.5 mg/L

Interferences:

(A) Thiocyanates: Thiocyanates are positive interferences.
(B) Sulfides: Sulfides can adversely effect the color procedure. Remove sulfide by precipitating with cadmium carbonate, and remove precipitate by filtration.

QC Requirements:

None.

Sample Handling:

Samples are collected in plastic bottles, and preserved with sodium hydroxide. If chlorine is present (test for chlorine using KI starch paper or superior method), add sufficient ascorbic acid to remove it. Samples are then refrigerated.

Max Holding Time:

14 days (MCAWW, Table 1).

Sample Prep Met

None.

Relative Cost:

Less than $50

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Method Summary Information