Page:NIOSH Manual of Analytical Methods - 6010.pdf/1

 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