National Institute for Occupational Safety and Health

“ Wear protective equipment (gloves, labcoats, and safety glasses) when working with HF. Do not use HF with glass labware. Perform all acid digestions in a fume hood. SAMPLING: 1. 2.
Calibrate each personal sampling pump with a representative sampler in line. Sample at an accurately known flow rate between 1 and 4 L/min for a total sample size of 200 to 1000 L. Do not exceed 2 mg total dust loading on the filter. ”

“ Prepare calibration graph (absorbance vs. solution concentration, μg/mL) . Analyze three quality control blind spikes and three analyst spikes to ensure that the recovery and calibration graph are in control (steps 6 through 14 and 17 through 19) . ”

“ ESTIMATED LOD: 50 μg soluble W per sample; 125 μg insoluble W per sample [2] PRECISION (Sr) :
0.029 [1]
APPLICABILITY: The working range of this method is 0.25 to 5 mg/m 3 (soluble) and 0.6 to 5 mg/m 3 (insoluble) for a 400-L air sample. This is an elemental analysis and not compound-specific. For cemented tungsten carbide samples, cobalt can be quantitatively determined from the HCl extract used to remove interferences.
INTERFERENCES: None known. Ni, Mo, V, Mn, Cr, Co and Fe do not interfere at concentrations up to 50 times the tungsten concentration [3] . ”