National Institute for Occupational Safety and Health

“ Methanol, reagent grade.* Analyte: dimethylacetamide, reagent grade, or dimethylformamide, reagent grade.* Acetone, reagent grade.* Desorption efficiency (DE) stock solution, 0.05 mg/mL. Prepare solutions of dimethylacetamide or dimethylformamide fresh daily in acetone. Hydrogen, prepurified. Air, filtered, compressed. Nitrogen, purified.
See SPECIAL PRECAUTIONS. 1. Sampler: glass tube, 7 cm long, 6-mm OD, 4-mm ID, with plastic caps, containing two sections of 20/40 mesh silica gel (front = 150 mg; back = 75 mg) separated by a 2-mm urethane foam plug. ”

“ Acetone and methanol are flammable and a dangerous fire and explosion risk. They are moderately toxic by ingestion and inhalation. Dimethylacetamide and dimethylformamide are strong irritants to skin and tissue and moderate fire risks. SAMPLING: 1. 2. 3. 4.
Calibrate each personal sampling pump with a representative sampler in line. Break ends of sampler immediately before sampling. Attach sampler to personal sampling pump with flexible tubing. Sample at an accurately known flow rate between 0.01 to 1 L/min for a total sample size of 15 to 80 L. Cap the samplers. ”

“ Desorption efficiency at 0.943, 1.886, and 3.77 mg per silica gel tube was 88.8, 93.8, and 94.9%, respectively. A storage study for five days at 1.866 mg per silica gel tube gave a recovery of 93.6%. Overall sampling and measurement precision, SˆrT, was 0.067. Method S255 for dimethylformamide was evaluated over the range of 11 to 61 mg/m 3 at an atmospheric temperature and pressure of 23 °C and 761 mm Hg using a 45-L sample [1] . Breakthrough occurred when a test atmosphere containing 119.5 mg/m 3 of dimethylformamide was sampled at 0.859 L/min for 146 min. ”