Page:NIOSH Manual of Analytical Methods - 2528.pdf/2

 2-NITROPROPANE: METHOD 2528, Issue 2, dated 15 August 1994 - Page 2 of 4 REAGENTS: 1. 2. 3.

4. 5. 6.

EQUIPMENT:

2-Nitropropane, chromatographic quality.* Ethyl acetate, chromatographic quality. Calibration stock solution, 9.82 mg/mL. Add 98.2 mg (100 µL) 2-nitropropane to a 10-mL volumetric flask. Dilute to the mark with ethyl acetate. Prepare in duplicate. Helium or nitrogen, purified. Hydrogen, prepurified. Air, filtered.



See SPECIAL PRECAUTIONS.

1. Sampler: glass tube, 7.0-cm long, 6.0-mm OD, 4-mm ID; two section of 60/80 mesh, acetone-washed, Chromosorb 106 (front = 100 mg; back = 50 mg) separated by a 2-mm section of urethane foam and held in place with plugs of silanized glass wool, flamesealed 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, FID, integrator and column (page 2528-1). 4. Vials, glass, 2-mL, PTFE-lined septum crimp caps. 5. Syringes, 1- to 10-µL, readable to 0.1 µL. 6. Volumetric flasks, 10-mL. 7. Pipet, delivery, 1.0-mL. 8. File.

SPECIAL PRECAUTIONS: 2-Nitropropane is a suspected human carcinogen [4]. Perform all work with this chemical 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 0.05 L/min for a total sample size of 0.1 to 2 L. NOTE: High pressure drop across the sampler may occur at flow rates 0.05 L/min, giving inaccurate sample volumes. Cap the samplers. Pack securely for shipment.

SAMPLE PREPARATION: 5. 6. 7.

Place the front and back sorbent sections of the sampler tube in separate vials. Discard the glass wool and foam plugs. Pipet 1.0 mL ethyl acetate into each vial. Cap each vial. Allow to stand 30 min with occasional agitation.

CALIBRATION AND QUALITY CONTROL: 8.

Calibrate daily with at least six working standards. a. Add known amounts of calibration stock solution to ethyl acetate in 10-mL volumetric flasks and dilute to the mark. Use serial dilutions as needed to obtain 2-nitropropane concentrations in the range 1 to 150 µg/mL. b. Analyze with samples and blanks (steps 11 and 12). c. Prepare calibration graph (peak area vs. µg 2-nitropropane). NIOSH Manual of Analytical Methods (NMAM), Fourth Edition, 8/15/94