National Institute for Occupational Safety and Health

“ Preparation of Reagent-Coated Glass Wool Dissolve 300 mg (0.00130 mole) N- [ (4-nitrophenyl) methyl] propylamine hydrochloride in 25 mL water in a 125-mL separatory funnel. Add 15 mL 1 M NaOH and shake the mixture. Extract the N- [ (4-nitrophenyl) -methyl] propylamine with 50 mL hexane. Transfer 40 mL of the hexane solution to a 50-mL beaker which is wrapped with aluminum foil and contains 1.82 g silanized glass wool. Under dim light, evaporate hexane from the beaker with the aid of a stream of nitrogen. Knead the glass wool with a glass rod to produce a uniform coating. ”

“ Determine recoveries from samplers in the range 0.3 to 25 μg 2,4-TDI per sample. Prepare three samples at each of three levels plus three media blanks. NOTE: Recoveries should be quantitative. If recoveries are not quantitative, determine the reason for error. ”

“ Continue to evaporate hexane until the glass wool appears dry. Protect the coated glass wool from bright light. The quantity of coated glass wool is sufficient for the preparation of the front and back sections for twenty samplers. ”