Page:NIOSH Manual of Analytical Methods - 6017.pdf/1

 HYDROGEN CYANIDE HCN

MW: 27.03

METHOD: 6017, Issue 1

6017

CAS: 74-90-8

RTECS: MW6825000

EVALUATION: PARTIAL

OSHA: 10 ppm (skim) NIOSH: STEL 4.7 ppm ACGIH: C 10 ppm (skin) (1 ppm = 1.105 mg/m3

Issue 1: 15 March 2003

PROPERTIES: gas; BP 26 ºC; vapor density 0.93 (air = 1.00); d(liq) 0.69 g/mL @ 20 ºC; VP 82.7 kPa (620 mm Hg) @ 20 ºC; explosive range 5 to 40% v/v in air

SYNONYMS: hydrocyanic acid, prussic acid, formonitrile

SAMPLING SAMPLER:

SOLID SORBENT TUBE (soda lime, 600 mg/200 mg) + glass fiber filter, 5-mm

FLOW RATE:

0.05 to 0.2 L/min

VOL-MIN: -MAX:

2 L @ 5 ppm 90 L

SHIPMENT:

routine

SAMPLE STABILITY:

at least 2 weeks @ 25 °C [1]

BLANKS:

2 to 10 field blanks per set

MEASUREMENT TECHNIQUE:

ION CHROMATOGRAPHY (IC) / DC AMPEROMETRY

ANALYTE:

CN!

DESORPTION:

10 mL deionized water; agitate; let stand 60 min

INJECTION LOOP VOLUME: 50 :L

ACCURACY RANGE STUDIED:

not determined

BIAS:

not determined

OVERALL PRECISION (Ö r T ):

not determined

ACCURACY:

not determined

ELUENT:

0.5 M NaAc 0.1 M NaOH 0.5% ethylenediamine

COLUMNS:

HPIC-AS7 or equivalent anion separator, HPIC-AG7 or equivalent anion micro guard

DETECTOR:

0.0 V applied Ag0 vs. AgCl reference

CALIBRATION:

standard solutions of KCN in 0.1 N NaOH

RANGE:

10 to 300 µg CN– per sample [2]

ESTIMATED LOD: 1 µg CN– per sample [2] PRECISION ( þ r ):

0.041

APPLICABILITY: 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.

OTHER METHODS: This method is based on NIOSH 6010 which uses the same collection procedure with a VISIBLE ABSORPTION detection system [4]. The method has been adapted for use with a Technicon Autoanalyzer [5]. NIOSH Method 7904 uses an ion-specific electrode for measurement and has been used to determine HCN in firefighting environments [6].

NIOSH Manual of Analytical Methods (NMAM), Fourth Edition