Page:NIOSH Manual of Analytical Methods - 5022.pdf/1

 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