Page:NIOSH Manual of Analytical Methods - 1604.pdf/2

 ACRYLONITRILE: METHOD 1604, Issue 2, dated 15 August 1994 - Page 2 of 4 REAGENTS: 1. 2. 3. 4. 5. 6. 7.

8. 9. 10.

EQUIPMENT:

Carbon disulfide, chromatographic quality.* Acetone, chromatographic quality. Hexane, reagent grade. Eluent: 2% acetone (v/v) in carbon disulfide.* Acrylonitrile, stabilized.* Stable at least one month at 4 °C. Acrylonitrile, freshly distilled.* Calibration stock solution, 4 µg/µL. Add 50 µL freshly distilled acrylonitrile to 10 mL hexane. Stable one week at 4 °C. Helium, purified. Hydrogen, prepurified. Air, filtered.
 * See Special Precautions

1. Sampler: glass tube, 7 cm long, 6-mm OD, 4mm ID, flame-sealed ends with plastic caps, containing two sections of activated (600 °C) coconut shell charcoal (front = 100 mg, back = 50 mg) separated by a 2-mm urethane foam plug. A silylated glass wool plug precedes the front section and a 3-mm urethane foam plug follows the back section. Pressure drop across the tube at 1 L/min airflow must be less than 3.4 kPa. Tubes are commercially available. 2. Personal sampling pump, 0.01 to 0.2 L/min, with flexible connecting tubing. 3. Gas chromatograph, flame ionization detector, integrator and column (page 1604-1). 4. Micro-distillation apparatus for vacuum distillation of acrylonitrile. 5. Vials, 2-mL, PTFE-lined crimp caps. 6. Syringe, 10-µL and other sizes as needed, readable to 0.1 µL. 7. Volumetric flasks, 10-mL. 8. Pipets, 1-mL, with pipet bulb.

SPECIAL PRECAUTIONS: Carbon disulfide is toxic and a severe fire and explosion hazard (flash point = -30 °C). Acrylonitrile is explosive, flammable, toxic, and a suspect carcinogen [3]. Work with these compounds only in a hood. SAMPLING: 1. 2. 3. 4.

Calibrate each personal sampling pump with a representative sampler in line. Break the ends of the sampler immediately before sampling. Attach sampler to personal sampling pump with flexible tubing. Sample at an accurately known flow rate between 0.01 and 0.2 L/min for a total sample size of 3.5 to 20 L. Cap the samplers pack securely for shipment.

SAMPLE PREPARATION: 5. 6. 7.

Place the front and back sorbent sections of the sampler tube in separate vials. Discard the glass wool and foam plugs. Add 1.0 mL eluent to each vial. Attach crimp cap to each vial. NOTE: An internal standard, e.g., 0.1% (v/v) benzene or n-hexane, may be added at this step. Allow to stand 30 min with occasional agitation.

CALIBRATION AND QUALITY CONTROL: 8.

Calibrate daily with at least five working standards over the range 1 to 1000 µg acrylonitrile per sample. a. Add known amounts of calibration stock solution, or a serial dilution thereof, to eluent in 10-mL volumetric flasks and dilute to the mark with eluent (2% acetone in CS 2). NIOSH Manual of Analytical Methods (NMAM), Fourth Edition, 8/15/94