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ARSENIC and compounds, as As
(except AsH₃ and As₂O₃)
(except AsH₃ and As₂O₃)
7900
As
MW: 74.92
CAS: 7440-38-2
RTECS: CG525000
METHOD: 7900, Issue 2
EVALUATION: PARTIAL
Issue 1: 15 February 1984
Issue 2: 15 August 1994
Issue 2: 15 August 1994
OSHA:
0.01 mg/m³
NIOSH:
C 0.002 mg/m³/15 min; carcinogen
ACGIH:
0.01 mg/m³; carcinogen
PROPERTIES:
soft, reactive metalloid; MP 848 °C;
SYNONYMS:
vary depending upon the compound
SAMPLING
SAMPLER:
FILTER
(0.8-μm cellulose ester membrane)
(0.8-μm cellulose ester membrane)
FLOW RATE:
1 to 3 L/min
VOL-MIN:
30 L @ 0.002 mg/m³
-MAX:
1000 L
SHIPMENT:
routine
SAMPLE STABILITY:
stable if refrigerated
BLANKS:
2 to 10 field blanks per set
ACCURACY
RANGE STUDIED:
not studied
BIAS:
see APPLICABILITY
OVERALL PRECISION (SˆrT):
not evaluated
ACCURACY:
not determined
MEASUREMENT
TECHNIQUE:
ATOMIC ABSORPTION, FLAME ARSINE
GENERATION
GENERATION
ANALYTE:
arsenic
ASHING:
conc. HNO₃, 3 mL; conc. H₂SO₄, 1
mL; conc. HClO 4, 1 mL; 140 °C
mL; conc. HClO 4, 1 mL; 140 °C
FINAL SOLUTION:
4% H₂SO₄, 25 mL
FLAME:
hydrogen-argon
WAVELENGTH:
193.7 nm
BACKGROUND CORRECTION:
D2 or H2 continuum
CALIBRATION:
As in 4% H₂SO₄
RANGE:
0.05 to 2.0 μg per sample [1]
ESTIMATED LOD:
0.02 μg per sample [1]
PRECISION (Ŝr):
0.11 [1]
APPLICABILITY:
The working range is 0.00025 to 0.01 mg/m ³ for a 200-L air sample and 0.002 to 0.07 mg/m ³ for a 30-L air sample. This method collects particulate arsenic only; if arsenic trioxide vapor is present, use the sampler in Method 7901. This is an elemental analysis, not compound specific. Volatile organic arsenic compounds, As 2O3 vapor, and arsine are not collected efficiently by this sampling method.
INTERFERENCES:
Background absorption is overcome by the use of D ₂ or H₂ continuum.
OTHER METHODS:
This revises P&CAM 139 [1]); a similar method appears in the criteria document [2]. Method 7901 uses a sampler designed to collect As ₂O₃ vapor and an alternate measurement technique (graphite furnace-AAS). Method 7300 (ICP-AES) also gives an alternate measurement technique.
NIOSH Manual of Analytical Methods (NMAM), Fourth Edition 8/15/94