Page:NIOSH Manual of Analytical Methods - 1020.pdf/2

 1,1,2-TRICHLORO-1,2,2-TRIFLUOROETHANE: METHOD 1020, Issue 2, dated 15 August 1994 - Page 2 of 4

REAGENTS:

EQUIPMENT:

1.	Carbon disulfide (CS2), chromatographic quality.* 2.	1,1,2-Trichloro-1,2,2-trifluoroethane (TTE), reagent grade.* 3.	Helium, purified. 4.	Hydrogen, prepurified. 5.	Air, filtered, compressed.
 * See SPECIAL PRECAUTIONS.

1.	Sampler: glass tube, 7 cm long, 6-mm OD, 4-mm ID, with flame-sealed ends with plastic caps, containing two sections of 20/40 mesh 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 0.05 L/min, with flexible connecting tubing. 3.	Refrigerant, bagged, and insulated shipping container. 4.	Gas chromatograph, flame ionization detector, integrator, and column (see page 1020-1). 5.	Vials, 2-mL, PTFE-lined caps. 6.	Syringes, 10- to 100-µL, readable to 0.5%. 7.	Volumetric flasks, 10-mL. 8.	Pipet, TD, 1-mL, with pipet bulb.

SPECIAL PRECAUTIONS: Carbon disulfide is toxic and a serious fire and explosion hazard (flash point = –30 °C). 1,1,2-Trichloro-1,2,2-trifluoroethane is a narcotic [4]. Work with these compounds only in a hood. SAMPLING: 1.	Calibrate each personal sampling pump with a representative sampler in line. 2.	Break the ends of the sampler immediately before sampling. Attach sampler to personal sampling pump with flexible tubing. 3.	Sample at an accurately known flow rate between 0.01 and 0.05 L/min for a total sample size of 0.1 to 3 L. 4.	Cap the samplers. Pack securely for shipment in a refrigerated container. SAMPLE PREPARATION: 5.	Place the front and back sorbent sections of the sampler tube in separate vials. Discard the glass wool and foam plugs. 6.	Add 1.0 mL CS2 to each vial. Cap each vial. 7.	Allow to stand 30 min with occasional agitation. CALIBRATION AND QUALITY CONTROL: 8.	Calibrate daily with at least six working standards in the range of 0.1 to 20 mg/mL. a.	 Add known amounts of TTE to CS2 in 10-mL volumetric flasks and dilute to the mark. b.	 Analyze with samples and blanks (steps 11 and 12). c.	 Prepare calibration graph (peak area vs. mg TTE).

NIOSH Manual of Analytical Methods (NMAM), Fourth Edition