Page:NIOSH Manual of Analytical Methods - 7900.pdf/1

 Rh

Rh

METHOD: 7900, Issue 2

0.01 mg/m³ C 0.002 mg/m³/15 min; carcinogen 0.01 mg/m³; carcinogen soft, reactive metalloid; MP 848 °C;

vary depending upon the compound

FILTER (0.8-μm cellulose ester membrane) 1 to 3 L/min 30 L @ 0.002 mg/m³ 1000 L routine stable if refrigerated 2 to 10 field blanks per set

not studied see APPLICABILITY not evaluated not determined

ATOMIC ABSORPTION, FLAME ARSINE GENERATION arsenic conc. HNO₃, 3 mL; conc. H₂SO₄, 1 mL; conc. HClO 4, 1 mL; 140 °C 4% H₂SO₄, 25 mL hydrogen-argon 193.7 nm D2 or H2 continuum As in 4% H₂SO₄ 0.05 to 2.0 μg per sample [1] 0.02 μg per sample [1] 0.11 [1]

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.

Background absorption is overcome by the use of D ₂ or H₂ continuum.

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