Page:NIOSH Manual of Analytical Methods - 1018-2.pdf/2

 DICHLORODIFLUOROMETHANE, 1,2-DICHLOROTETRAFLUOROMETHANE, CHLOROFLUOROMETHANE: METHOD 1018, Issue 2, dated 15 August 1994, Page 2 of 4

REAGENTS: 1. 2. 3. 4. 5. 6. 7. 8.

EQUIPMENT:

Chlorodifluoromethane, 99% Dichlorodifluoromethane, 99% 1,2-Dichlorotetrafluoroethane, 99% Methylene chloride*, distilled in glass. Nitrogen, purified. Hydrogen, prepurified Air, filtered, compressed. Helium, purified



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 with plastic caps, containing two sections of activated (600 °C) coconut shell charcoal (1st 400 mg/200 mg; 2nd 100 mg/50 mg), front and back sections 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 25 mm/Hg. Tubes are commercially available. 2. Personal sampling pump, 0.01 to 0.05 mL/min, with flexible connecting tubing. 3. Gas chromatograph with a FID detector, recorder, integrator and column (page 1018-1). 4. Bottles, 22-mL, PTFE-lined septum screw caps. 5. Syringes, gas-tight, 10-mL and other sizes as needed. 6. Pipet, TD, 20-mL, with pipet bulbs. 7. DE apparatus. Glass or plastic T equipped with septum in one arm to allow introduction of analyte to a flowing stream of nitrogen.

SPECIAL PRECAUTIONS: Methylene chloride is an irritant, can be absorbed through the skin, and is a suspect carcinogen [4]. Prepare samples 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 0.5 L/min for a total sample size of 1 to 4 L. Separate and cap the tubes. Pack securely for shipment in an insulated container with bagged refrigerant.

SAMPLE PREPARATION:

5. 6. 7.

NOTE: Refrigerate samples at -10 °C if not analyzed immediately. Pipet 20.0 mL methylene chloride into a series of bottles. Place both sections of the front sampler tube into a bottle containing solvent, discarding the glass wool and foam plugs. Immediately cap and gently shake the bottle. Analyze within 6 hrs. Perform step 6 for the back sampler tube.

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