National Institute for Occupational Safety and Health

“ Prepare working standards by pipetting 0- to 10-mL aliquots of the 15 μg/mL standard solution into clean vials. Bring the total volume to 15 mL with distilled water. Follow steps 10 and 11 to analyze the working standards. c. Prepare a calibration graph (absorbance vs. μg per sample) . Determine recovery at least once for each lot of filters used. a. Place eight filters on a plastic test tube rack. Using an adjustable pipette, add to the center of each filter 0, 7.5, 15, 30, 45, 60, 90, 120, and 150 μL of 1000-μg/mL calibration stock solution. Let filters air dry overnight at room temperature. ”

“ Volumetric flasks, 25-, 100-, 200- and 250-mL capacity. 13. Miscellaneous: tweezers, microspatula, rubber suction bulb, wood applicator stick weighing paper, filter paper and filter funnel with stand.
SPECIAL PRECAUTIONS: Bromine is very SAMPLING: corrosive and causes severe burns; vapors are extremely irritating and toxic. Wear gloves and 1. Calibrate each personal sampling pump handle only in a hood. with a representative sampler in line. 2. Sample at an accurately known flow rate Ethylene thiourea is an animal teratogen and between 1 and 3 L/min for a total sample carcinogen [3,4] . ”

“ Bromine, Br 2, ACS reagent.* Disodium pentacyanonitrosyl ferrate dihydrate (sodium nitroferricyanide; sodium nitroprusside) , Na 2Fe (CN) 5NO·2H 2O, ACS reagent. 3. Hydroxylamine hydrochloride, NH 2OH·HCl, ACS reagent. 4. Sodium bicarbonate, NaHCO 3, ACS reagent. 5. Hexane, spectrophotometric quality. 6. ”