Method 7904

Cyanides, Particulate and Gaseous

This method is used for the collection and analysis of particulate and gaseous cyanides.  The sample is collected on polyvinyl chloride membrane filter (PVC) and in a 0.1N KOH bubbler.  After sampling, the filter is extracted with KOH and analyzed by ion specific electrode (ISE).  The bubbler contents are also analyzed by ISE.

The working range of the method (as CN­) is 0.5 to 15 mg/m³ for a 90L air sample, or 5 to 20 mg/m³ for a 10L air sample.

In humid atmospheres, some particulate cyanide collected on the filter will liberate hydrogen cyanide which will be trapped in the bubbler.  The method can't distinguish between HCN formed in this manner and the HCN native to teh sampling atmosphere.

NOTE:  This method combines and replaces Methods S288, S250, and P&CAM 116.

(NIOSH Issue 2: 15 August 1994)


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Method Data

Hold Times, Preservatives, Preps, Collection, Analytical & Documentation
Holding Time:   Analyze within 5 days; particulate on filter may liberate HCN gas.
Preservatives:   None noted in method
Required Preps:   PVC filter 0.8-µm pore size (SKC 225-2705) and 0.1N KOH impinger solution
Collection Method:   The method recommends a 0.5 - 1 L/min. flow rate with a 10 - 180L sample collection volume.
Analytical Methodology:   ISE
Documentation:   7904

Analyte List*

Analyte Formula CAS Number Detection Limit
Potassium cyanide
Hydrogen cyanide

* The analytes and detection limits listed for each method represent the typical detection limits and analytes reported for that particular method. Keep in mind that analyte lists may vary from laboratory to laboratory. Detection limits may also vary from lab to lab and are dependent upon the sample size, matrix, and any interferences that may be present in the sample.