Page:NIOSH Manual of Analytical Methods - 2017.pdf/2

 ANILINE, o-TOLUIDINE, AND NITROBENZENE: METHOD 2017, Issue 1, dated 15 January 1998 - Page 2 of 5

REAGENTS:

EQUIPMENT:

1.	Aniline, reagent grade.* 2.	o-Toluidine, reagent grade.* 3.	Nitrobenzene, reagent grade.* 4.	Ethanol, chromatographic grade.* 5.	Sulfuric acid (H2SO4), reagent grade,* 0.26 N. Dilute 1.5 mL of 36 N H2SO4 to 200 mL with deionized water. 6.	Aniline calibration stock solution, 102.2 mg/ mL. Dilute 1 mL aniline to 10 mL with ethanol. 7.	o-Toluidine calibration stock solution, 100.6 mg/mL. Dilute 1 mL o-toluidine to 10 mL with ethanol. 8.	Nitrobenzene calibration stock solution, 120.3 mg/mL. Dilute 1 mL nitrobenzene to 10 mL with ethanol. 9.	Helium, purified. 10.	Hydrogen, prepurified. 11.	Air, filtered.
 * See SPECIAL PRECAUTIONS

1.	Sampling train: Filter, glass fiber, 37-mm (Gelman, or equivalent) treated with 0.26 N H2SO4 (see APPENDIX) in polystyrene cassette. Filters are commercially available (SKC, Inc. #225-9004, or equivalent). Sorbent tube, glass tube, 11 cm, 8-mm OD, containing two sections of silica gel (front = 520 mg/back = 260 mg) separated and retained by polyurethane foam plugs. A silylated glass wool plug precedes the front section. Tubes are commercially available (SKC, Inc. #226-15, Supelco ORBO-507). 2.	Personal sampling pump, 0.2 L/min, with flexible connecting tubing. 3.	Gas chromatograph, flame ionization detector, integrator, and column (page 2017-1). 4.	Ultrasonic bath. 5.	Vials, autosampler, with PTFE-lined caps. 6.	Vials, 4-mL, with screw caps. 7.	Microliter syringes, 10-µL and other sizes as needed, readable to 0.1 µL. 8.	Flasks, volumetric, various sizes. 9.	Pipets, various sizes.

SPECIAL PRECAUTIONS: Aniline is toxic, poisonous and a potential human carcinogen. o-Toluidine is toxic and a potential human carcinogen. Nitrobenzene is toxic and poisonous. Nitrobenzene has a synergistic effect on the toxicity of aniline and o-toluidine [5]. Ethanol is flammable and a dangerous fire risk. Wear appropriate protective clothing and work with these compounds in a well ventilated hood. SAMPLING: 1.	Calibrate each personal sampling pump with a representative sampler in line. 2.	Assemble sampling train. Attach filter cassette to sorbent tube and to personal sampling pump with flexible tubing. 3.	Sample at an accurately known flow rate (0.2 L/min) for a total sample size of 5 to 50 L. NOTE:	High relative humidity reduces the sampling capacity of the silica gel sorbent. 4.	Separate the cassettes and tubes, cap, and pack securely for shipment. SAMPLE PREPARATION: 5.	Place front (include glass wool plug) and back sorbent sections of the sampler tube in separate 4-mL vials. Discard foam plugs. Remove glass fiber filters from cassettes and place in 4-mL vials. 6.	Add 2 mL of ethanol to each vial and cap. 7.	Place vials in an ultrasonic bath for 60 min to aid desorption. 8.	Transfer 1-mL aliquot to autosampler vials and attach crimp caps.

NIOSH Manual of Analytical Methods (NMAM), Fourth Edition