Page:NIOSH Manual of Analytical Methods - 1011.pdf/2

 ETHYL BROMIDE: METHOD 1011, Issue 2, dated 15 August 1994 - Page 2 of 4 REAGENTS: 1. 2. 3.

4. 5. 6.

EQUIPMENT:

2-Propanol, chromatographic grade.* Ethyl bromide, reagent grade.* Calibration stock solution, 0.073 mg/µL. Dilute 0.5 mL ethyl bromide to 10 mL with 2-propanol. Nitrogen or helium, purified. Hydrogen, prepurified. Air, filtered, compressed.



See SPECIAL PRECAUTIONS.

1. Sampler: glass tube, 7 cm long, 6-mm OD, 4-mm 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, FID, integrator and column (page 1011-1). 4. Vials, glass, 2-mL, PTFE-lined caps. 5. Syringes, 10-µL and other convenient sizes for preparing standards, readable to 0.1 µL. 6. Volumetric flasks, 10-mL. 7. Pipets, 1- and 5-mL, with pipet bulb.

SPECIAL PRECAUTIONS: Ethyl bromide is flammable, a dangerous fire hazard (flash point = 26 °C), respiratory irritant, narcotic, and a hepato- and renal toxin [4]. 2-Propanol is flammable and a dangerous fire risk with a flash point of 11 °C. 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 0.5 to 4 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 2-propanol to each vial. Attach crimp cap to each vial. Allow to stand overnight with occasional agitation.

CALIBRATION AND QUALITY CONTROL: 8.

Calibrate daily with at least six working standards over the range 0.02 to 10 mg ethyl bromide per sample. a. Add known amounts of ethyl bromide or calibration stock solution to 2-propanol in 10-mL volumetric flasks and dilute to the mark. Make serial dilutions as necessary to obtain solutions in the range 0.02 to 10 mg ethyl bromide/mL. NIOSH Manual of Analytical Methods (NMAM), Fourth Edition, 8/15/94