Standard Methods: 4500-CN-G: Cyanides Amenable to Chlorination

Summary
Analytes
Revisions
Data and Sites

Official Method Name

4500-CN- G. Cyanides Amenable to Chlorination after Distillation

Current Revision

Standard Methods Online

Media

WATER

Instrumentation

Spectroscopy (Colorimetry; Photometry)

Method Subcategory

Inorganic

Method Source

Standard Methods

Citation

Standard Methods Online - Standard Methods for the Examination of Water and Wastewater

Brief Method Summary

After part of the sample is chlorinated to decompose the cyanides, both the chlorinated and the untreated sample are subjected to distillation as described in Section 4500-CN-.C. The difference between the CN- concentrations found in the two samples is expressed as cyanides amenable to chlorination. Different analytical methods (e.g., colorimetry, titrimetry) may be used in final analyses, depending on required sensitivity.

Scope and Application

This method is applicable to the determination of cyanides amenable to chlorination (CATC) in water.

Applicable Concentration Range

Interferences

Some unidentified organic chemicals may oxidize or form breakdown products during chlorination, giving higher results for cyanide after chlorination than before chlorination. This may lead to a negative value for cyanides amenable to chlorination after distillation for wastes from, for example, the steel industry, petroleum refining, and pulp and paper processing. Where such interferences are encountered use Method 4500-CN-.I Weak Acid Dissociable Cyanide for determining dissociable cyanide.

Quality Control Requirements

See Section 4020 Quality Assurance/Quality Control.

Sample Handling

Protect sample from exposure to ultraviolet radiation, and perform manipulations under incandescent light, to prevent photodecomposition of some metal-cyanide complexes by ultraviolet light. Add 0.6 g ascorbic acid if chlorine is present and refrigerate.

Maximum Holding Time

General: 24 hours; Regulatory: 14 days (no sulfide present), or 24 hours (sulfide present) (See Section 1060)

Relative Cost

Less than $50

Sample Preparation Methods

This method has 1 analyte associated with it.

Analyte	Detection Level	Bias	Precision	Pct False Positive	Pct False Negative	Spiking Level
Available Cyanide(E-10275) Amenable cyanide Available Cyanide Cyanide amenable to chlorination	N/A	113% Rec (ML)	37.00 % RSD (ML)			0.01 mg/L

Precision Descriptor Notes:	Precision and bias data based on the results of eight operators in seven laboratories. Data for reagent water and selected water matrices are given in a table in the method. The data in NEMI were generated using 21 analyses of reagent water using colorimetry.
Detection Level Note:

Revision	PDF/Link
Standard Methods Online
Standard Methods 18th Edition (1992)
Standard Methods 19th Edition (1995)
Standard Methods 18th, 19th, 20th ed.

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Standard Methods: 4500-CN-G: Cyanides Amenable to Chlorination

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