ARSENIC TRIOXIDE, as As
As2O3
MW: 197.84
METHOD: 7901, Issue 2
CAS: 1327-53-3
7901
RTECS: CG3325000
EVALUATION: FULL
OSHA : 0.01 mg/m 3 (As) NIOSH: C 0.002 mg/m 3 (As)/15 min; carcinogen ACGIH: 0.01 mg/m 3; carcinogen
PROPERTIES:
Issue 1: 15 February 1984 Issue 2: 15 August 1994
solid; MP 275 °C or 313 °C (sublimes); VP 0.0075 Pa (5.6 x 10 -5 mm Hg; 0.45 µg As/m 3 ) @ 25 °C
SYNONYMS: arsenous acid anhydride; arsenous sesquioxide; arsenolite; claudetite
SAMPLING SAMPLER:
FILTER (Na 2 CO 3 -impregnated, 0.8-µm cellulose ester membrane + backup pad)
MEASUREMENT TECHNIQUE:
ATOMIC ABSORPTION, GRAPHITE FURNACE
ANALYTE:
arsenic
FLOW RATE: 1 to 3 L/min VOL-MIN: -MAX:
30 L @ 0.01 mg/m 3 1000 L
SHIPMENT:
routine
ASHING:
15 mL HNO
FINAL SOLUTION:
10 mL 1% HNO 3 , 0.1% Ni 2+
WAVELENGTH:
193.7 nm; D 2 or H 2 correction
SAMPLE STABILITY:
stable
GRAPHITE TUBE: pyrolytic
BLANKS:
2 to 10 field blanks per set
GRAPHITE FURNACE:
ACCURACY
3 + 6 mL H 2O 2; 150 °C
DRY: 100 °C, 70 sec; CHAR: 1300 °C, 30 sec; ATOMIZE: 2700 °C, 10 sec
INJECTION:
25 µL
RANGE STUDIED:
0.67 to 32 µg/m 3 [1,2] (400-L samples)
CALIBRATION:
As in 1% HNO 3 , 0.1% Ni 2+
BIAS:
- 0.55%
RANGE:
0.3 to 13 µg per sample
ˆ ): 0.075 [1,2] OVERALL PRECISION (S rT ACCURACY:
ESTIMATED LOD: 0.06 µg per sample
± 11.9% PRECISION (Sr):
0.029 [3,4]
APPLICABILITY: The working range is 0.001 to 0.06 mg/m 3 for a 200-L air sample. This method collects particulate arsenic compounds as well as arsenic trioxide vapor. If only total particulate arsenic is of interest, the use of the treated filter and analysis of the backup pad is not required. Arsine is not collected by this sampling method.
INTERFERENCES: Background absorption is overcome by the use of a deuterium background corrector. Matrix modification with Ni 2+ solution allows the use of a higher char temperature in the graphite furnace. Other particulate arsenic compounds will interfere.
OTHER METHODS: This method combines and replaces P&CAM 346 [3], S309 [4], and P&CAM 286 [5]. Method 7300 (ICP-AES) and arsine generation (Method 7900 and the criteria document method [1]) are for particulate arsenic compounds. Other me thods (P&CAM 173 [7], P&CAM 180 [8], and P&CAM 188 [9]) have not been revised because of interferences or poor sensitivity.
NIOSH Manual of Analytical Methods (NMAM), Fourth Edition, 8/15/94
