HYDROGEN CYANIDE
HCN
MW: 27.03
METHOD: 6010, Issue 2
CAS: 74-90-8
6010
RTECS: MW6825000
EVALUATION: FULL
OSHA : 10 ppm (skin) NIOSH: STEL 4.7 ppm ACGIH: C 10 ppm (skin) (1 ppm = 1.105 mg/m3 @ NTP)
PROPERTIES:
Issue 1: 15 May 1989 Issue 2: 15 August 1994
gas; BP 26 °C; vapor density 0.93 (air = 1.00); d(liq) 0.69 g/mL @ 20 °C; VP 82.7 kPa (620 mm Hg) @ 20 °C; 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)
MEASUREMENT TECHNIQUE:
SPECTROPHOTOMETRY, VISIBLE ABSORPTION
ANALYTE:
cyanide ion complex
DESORPTION:
10 mL deionized water; stand 60 min
FLOW RATE: 0.05 to 0.2 L/min VOL-MIN: -MAX:
2 L @ 5 ppm 90 L
SHIPMENT:
routine
COLOR DEVELOPMENT:
SAMPLE STABILITY:
at least 2 weeks @ 25 °C [1]
BLANKS:
2 to 10 field blanks per set
N-chlorosuccinimide/ succinimide oxidizing agent and barbituric acid/pyridine coupling agent; absorption @ 580 nm in 1-cm cuvette
CALIBRATION:
standard solutions of KCN in 0.1 N NaOH
RANGE:
10 to 300 µg CN- per sample [1]
ESTIMATED LOD:
1 µg CN- per sample [1]
PRECISION (Sr):
0.041 @ 10 to 50 mg per sample [1]
ACCURACY RANGE STUDIED:
2 to 15 mg/m3 [1] (3-L samples)
BIAS:
Not significant
ˆ ): 0.076 [1] OVERALL PRECISION (S rT ACCURACY:
± 15.0%
APPLICABILITY: The working range is 0.3 to 235 ppm (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 nd a subject to fewer interferences than NIOSH Method 7904, which uses ion specific electrode analysis. The method was usedot determine HCN in firefighting environments [2].
INTERFERENCES: A high concentration of hydrogen sulfide gives a negative interference.
OTHER METHODS: This is based on the method of Lambert, et al. [3]. NIOSH Method 7904 uses an ion specific electrode for measurement. The method has been adapted for use with a Technicon Autoanalyzer [4].
NIOSH Manual of Analytical Methods (NMAM), Fourth Edition, 8/15/94
