National Institute for Occupational Safety and Health

“ When the fume sample is visually clear of air bubbles and wet throughout, apply a vacuum of 10 to 15 PSIG (69 to 103 kPa) . Release the vacuum. e. Place a 47-mm, 5-μm cellulose ester membrane filter on the surface of water to wet it, remove excess water by blotting with tissue, and place it concentrically on top of the 37-mm filter. Press the surface of the top filter with a clean tissue to insure that no air bubbles remain between any of the filters. f. Mount the upper part of the filtration unit, add 5 mL of distilled water, and allow vacuum to draw water through the filters. ”

“ The size of the copper fume was 0.04 to 0.14 μm by electron microscopy and the collection efficiency of the sampler for this fume was 1.00 [1,4,9] . The dust-fume separation step was evaluated with samples laden with copper fume generated from copper welding; the samples were then placed into a dust generation system and overlaid with a known deposition of copper sulfate dust. With a dust loading of about 600 μg CuSO 4 and fume concentrations of 0.13 to 0.59 mg/m 3, an average of 96.5% of the dust was removed. ”

“ Aspirate a standard for every 10 samples to check instrument drift. Check analytical recoveries with at least one spiked media blank per 10 samples. Use method of additions occasionally to check for interferences. ”