National Institute for Occupational Safety and Health

“ The working range is 0.3 to 235 ppm (0.3 to 260 mg/m3 ) for a 3-L air sample. This method is applicable to STEL measurements. Particulate cyanides are trapped by the initial glass fiber membrane disk. This method is more sensitive and subject to fewer interferences than NIOSH Method 7904, which uses ion-specific electrode analysis [3] .
INTERFERENCES: A high concentration of hydrogen sulfide gives a negative interference. Any component with the same retention time as cyanide will interfere. ”

“ SAMPLE PREPARATION: 5. Score each sampler with a file. Break sampler at score line. 6. Transfer front and back sorbent sections to separate vials. Discard glass wool plugs separating and retaining sorbent sections. NOTE: An estimate of particulate cyanide may be obtained by analyzing the initial glass fiber filter disk as follows; however, no evaluation data are available for particulate cyanides determined in this m anner: a. Trans fer the glass fiber disk a nd glass woo l plug im m ediately behind it at the tube inlet to a third vial. ”

“ Autosam pler. Autosampler vials. Vials, 15- to 20-mL, for sample preparation. In-line filters, 0.45-μm. Micropipettors with disposable tips. Flasks, volumetric, 25-, 50-, 100-, 1000-mL, with stoppers Pipettes, transfer, disposable.
SPECIAL PRECAUTIONS: HC N gas and cyanide particu late s are highly toxic and m ay be fa tal if swallowed, inhaled, or absorbed through the skin [7] . Soda lime and NaO H are very caustic [7] . Use gloves and a fume hood when handling these chemicals.
SAMPLING: 1. Calibrate each personal sampling pump with a representative sampler in line. 2. ”