ARSENIC, organo-
(1) CH3AsO3H2 (2) (CH3)2AsO2H (3) H2NC6H4AsO3H
MW: (1) 139.96 (2) 137.99 (3) 217.07
METHOD: 5022, Issue 2
5022
CAS: (1) 124-58-3 (2) 75-60-5 (3) 98-50-0
RTECS: (1) PA1575000 (2) CH7525000 (3) CF7875000
EVALUATION: FULL
OSHA : 0.5 mg/m 3 (as As) NIOSH: no REL ACGIH: 0.2 mg/m 3 (as As)
PROPERTIES:
Issue 1: 15 May 1985 Issue 2: 15 August 1994
solids; MP (1) 161 °C, (2) 195 °C; (3) 232 °C
SYNONYMS: (1) Methylarsonic acid: methanearsonic acid. (2) Dimethylarsinic acid: cacodylic acid; hydroxydimethyl arsine oxide. (3) p-Aminophenyl arsonic acid: p-arsanilic acid; atoxylic acid. SAMPLING
MEASUREMENT
SAMPLER:
FILTER (1-µm PTFE)
TECHNIQUE:
ION CHROMATOGRAPHY/ HYDRIDE ATOMIC ABSORPTION
FLOW RATE:
1 to 3 L/min
ANALYTE:
anions (IC); AsH 3 (AAS)
VOL-MIN: -MAX:
50 L @ 0.01 mg/m 3 1000 L
EXTRACTION:
borate-carbonate buffer, 25 mL
SHIPMENT:
routine
SAMPLE STABILITY:
stable
BLANKS:
2 to 10 field blanks per set
ION CHROMATOGRAPHY: INJECTION LOOP VOLUME: COLUMNS: ELUENT:
0.8 mL two, 3 x 150-mm anion borate-carbonate buffer; 2.5 mL/min; 3450 kPa (500 psi); ambient temperature
AAS: QUARTZ FURNACE: WAVELENGTH:
800 °C 193.7 nm (no D 2)
CALIBRATION:
organoarsenicals in water
RANGE:
0.5 to 2 µg As per sample
ESTIMATED LOD:
0.2 µg As per sample [1]
PRECISION (Sr):
Table 1
ACCURACY RANGE STUDIED:
0.005 to 0.2 mg/m 3 [1,2]
BIAS:
not significant
ˆ ): 0.047 @ 0.02 mg/m 3 [1]; OVERALL PRECISION (S rT 0.14 @ 0.005 mg/m 3 [1] ACCURACY:
± 20% @ 0.02 mg/m 3
APPLICABILITY: The working range is 0.005 to 10 mg/m 3 (as As) for a 100-L air sample. The method is designed to quantitate particulate organo-arsenic compounds.
INTERFERENCES: Inorganic arsenic (III) co-elutes with dimethylarsenic acid using Eluent A but the two may be separated with Eluent B. Other ions at high concentrations in the sample can interfere with the chromatographic separation of the arsen icals. As 2O 3 is not efficiently sampled by this sampler; for quantitation of that compound see Method 7901.
OTHER METHODS: This is P&CAM 320 in revised format [2]. Method 7200 measures total As by hydride/AAS. Method 7901 measures As 2O 3, which can exist as a vapor and aerosol.
NIOSH Manual of Analytical Methods (NMAM), Fourth Edition, 8/15/94
