Page:NIOSH Manual of Analytical Methods - 1001.pdf/2

 METHYL CHLORIDE: METHOD 1001, Issue 2, dated 15 August 1994 - Page 2 of 4 REAGENTS: 1. 2. 3. 4. 5.

EQUIPMENT:

Methylene chloride (CH 2Cl2), chromatographic quality, methyl chloride-free.* Methyl chloride, 99.5%.* 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 0.1 L/min, with flexible connecting tubing. 3. Refrigerant, bagged (e.g., "Blue Ice") and insulated shipping container. 4. Gas chromatograph, flame ionization detector, integrator, and column (see page 1001-1). 5. Bottles, glass, 15-mL, with PTFE-lined septum crimp caps. 6. Syringes, gas-tight, 10-µL, and 0.1- to 1-mL. 7. Pipet, TD, 3-mL. 8. DE apparatus. Glass tubing, through which nitrogen flows at ca. 30 mL/min, with T-connection and septum.

SPECIAL PRECAUTIONS: Methyl chloride has poor warning properties, is a narcotic and a suspect carcinogen and teratogen [5,6]. Methylene chloride is a suspect carcinogen [6,7].

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, with the smaller tube nearer the sampling pump. Sample at an accurately known flow rate between 0.01 and 0.1 L/min for a total sample size of 0.4 to 3 L (e.g., at 0.1 L/min for 15 min for STEL measurement and 0.01 L/min for 50 to 300 min for TWA measurement). Separate and cap the tubes. Pack securely for shipment in an insulated container with bagged refrigerant.

SAMPLE PREPARATION: 5. 6.

Pipet 3.0 mL CH 2Cl2 into each of several bottles. Place, in order, the back and front sorbent sections of the front sampler tube into a bottle, discarding the glass wool and foam plugs. Immediately cap and gently shake the bottle. Analyze within 6 h.

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