Page:NIOSH Manual of Analytical Methods - 2527.pdf/2

 NITROMETHANE: METHOD 2527, Issue 2, dated 15 August 1994 - Page 2 of 4 REAGENTS: 1. 2. 3.

4. 5. 6.

EQUIPMENT:

Nitromethane, chromatographic quality.* Ethyl acetate, chromatographic quality. Calibration stock solution, 0.1138 mg/µL. Add 1.138 g (1.00 mL) nitromethane to a 10-mL volumetric flask. Dilute to the mark with ethyl acetate. Helium or nitrogen, purified. Hydrogen, prepurified. Air, filtered.



See SPECIAL PRECAUTIONS.

1. Sampler: glass tube, 10.0-cm long, 10-mm OD, 8-mm ID; two sections of 60/80 mesh Chromosorb 106 (front = 600 mg; back = 300 mg) separated by a plug of silanized glass wool and held in place with plugs of silanized glass wool, flame-sealed at both ends; with plastic caps. Tubes are commercially available. (SKC Cat. No. ST 226-111, or equivalent). 2. Personal sampling pump, 0.01 to 0.05 L/min, with flexible connecting tubing. 3. Gas chromatograph, nitrogen-phosphorus detector, integrator and column (page 2527-1). 4. Vials, glass, 5-mL, PTFE-lined septum, screwcaps. 5. Syringes, 1- to 25-µL, readable to 0.1 µL. 6. Volumetric flasks, 10-mL. 7. Pipets, delivery, 1- and 5-mL. 8. File.

SPECIAL PRECAUTIONS: Nitromethane vapor forms highly explosive mixtures with air. When highly confined and heated, it can detonate [3].

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 0.05 L/min for a total sample size of 1.2 to 3 L. NOTE: High pressure drop across the sampler may occur at flow rates above 0.05 L/min, giving inaccurate sample volumes. Immediately following sampling, remove the silanized glass wool from the end of the sampler nearer the pump and empty the 300-mg back sorbent section into a clean vial. Seal the vial with a PTFE-lined cap. Cap the tubes containing the front section. Pack securely for shipment.

SAMPLE PREPARATION: 5. 6. 7.

Place the front sorbent section of the sampler tube in a separate vial from that containing the back sorbent section. Discard the glass wool plugs. Pipet 5.0 mL ethyl acetate into each vial. Immediately cap each vial. Allow to stand 30 min with occasional agitation.

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