Page:NIOSH Manual of Analytical Methods - 1017.pdf/2

 TRIFLUOROBROMOMETHANE: METHOD 1017, Issue 2, dated 15 August 1994 - Page 2 of 4 REAGENTS: 1. 2. 3. 4. 5.

EQUIPMENT:

Methylene chloride (CH 2Cl2), chromatographic quality.* Trifluorobromomethane, 99%. Nitrogen, purified. Hydrogen, prepurified. Air, filtered, compressed.



See SPECIAL PRECAUTIONS.

1. Sampler: two glass tubes (9 cm long, 8-mm OD, 6-mm ID, followed by 7 cm long, 6-mm OD, 4-mm ID) connected in series with a short piece of tubing, flame-sealed ends and plastic end caps. Each tube contains two sections of 20/40 mesh activated (600 °C) coconut shell charcoal (front tube = 400 mg + 200 mg; back tube = 100 mg + 50 mg) separated by a 2-mm urethane foam plug. A silylated glass wool plug precedes each front section and a 3-mm urethane foam plug follows each back section. Pressure drop across the tubes at 1 L/min airflow must be less than 3.4 kPa. Tubes are commercially available. 2. Personal sampling pump, 0.01 to 0.05 L/min, with flexible connecting tubing. 3. Gas chromatograph, flame ionization detector, integrator, and column (see page 1017-1). 4. Vials, 10-mL, PTFE-lined caps. 5. Syringes, gas tight, 10-µL to 3-mL. 6. Volumetric flasks, 10-mL. 7. Pipet, TD, 5-mL. 8. DE apparatus. Glass tubing, through which nitrogen flows at ca. 200 mL/min, with T-connection and septum. Wrap outlet of tubing with heating tape and connect tubing to inlet of test sampler.

SPECIAL PRECAUTIONS: Methylene chloride is a suspect carcinogen and is metabolized to carbon monoxide, a toxic gas [3].

SAMPLING: 1. 2. 3. 4.

Calibrate each personal sampling pump with a representative sampler in line. Break the ends of the sampler tubes immediately before sampling. Attach sampler to personal sampling pump with flexible tubing with the smaller tube nearer the sampling pump. Sample at an accurately known flow rate between 0.01 and 0.05 L/min for a total sample size of 0.1 to 1 L. Separate and cap the tubes. Pack securely for shipment in an insulated container with dry ice.

SAMPLE PREPARATION: 5. 6.

7.

Pipet 5.0 mL chilled CH 2Cl2 into a series of vials. Place the front and back sorbent sections of the front sampler tube in a vial. Discard the glass wool and foam plugs. Immediately cap the vial. Similarly place the front and back sorbent sections of the back sampler tube in a separate vial. Allow to stand 30 min with occasional agitation. Analyze within 6 h.

NIOSH Manual of Analytical Methods (NMAM), Fourth Edition, 8/15/94