Page:NIOSH Manual of Analytical Methods - 5518.pdf/2

 NAPHTHYLAMINES, α- and β-: METHOD 5518, Issue 2, dated 15 August 1994 - Page 2 of 4 REAGENTS:

EQUIPMENT:

α-Naphthylamine and β-naphthylamine.* 2-Propanol. Acetic acid, glacial. Eluent, 0.05% (v/v) acetic acid in 2-propanol. Calibration stock solution, 500 µg/mL.* Weigh 5 mg of each analyte into a 10-mL volumetric flask. Dilute to volume with eluent. Prepare in duplicate. Stable one month if refrigerated. 6. Hydrogen, purified. 7. Helium, purified. 8. Air, compressed, filtered.

1. 2. 3. 4. 5.



See SPECIAL PRECAUTIONS.

1. Sampler (Fig. 1): high-efficiency glass fiber filter (Gelman Spectrograde or equivalent), 13-mm diameter, followed by 100 mg and 50 mg beds of 20/45 mesh silica gel. Tubes are commercially available. NOTE: Some other glass fiber filters contained an impurity with the same GC retention time as α-naphthylamine [1]. 2. Personal sampling pump, 0.2 to 0.8 L/min, with flexible connecting tubing. 3. Insulated container, with dry ice. 4. Gas chromatograph, FID and column (page 5518-1). 5. Test tubes, 1-mL, with polyethylene stoppers. 6. Syringes, glass, 5- and 10-µL, readable to 0.1 µL. 7. Pipet, TD, 0.5-mL. 8. Volumetric flasks, low actinic, 10-mL. 9. Centrifuge. 10. Balance, analytical. 11. Test tube shaker, vortex type.

SPECIAL PRECAUTIONS: The naphthylamines are recognized human bladder carcinogens [3, 4]. SAMPLING: Avoid all contact with them. Use a glove box for preparation of standard solutions. Dispose of all 1. Calibrate each personal sampling pump unneeded solutions in accordance with accepted with a representative sampler in line. procedures for carcinogens. 2. Attach sampler to personal sampling pump with flexible tubing. 3. Sample at an accurately known flow rate between 0.2 and 0.8 L/min for a total sample size of 30 to 100 L. 4. Cap the samplers. Pack securely for shipment in dry ice.

SAMPLE PREPARATION: 5. 6.

7. 8.

Bring samples to room temperature. Place glass fiber filter and 100-mg section of silica gel in a test tube. Place the 50-mg section of silica gel in a separate test tube. Desorb PTFE rings and stainless steel screens with the appropriate stages. Discard sampler caps. Add 0.5 mL eluent to each vial. Cap each test tube and mix with test tube shaker. Allow to stand 60 min with occasional agitation.

CALIBRATION AND QUALITY CONTROL: 9.

Calibrate daily with at least six working standards. a. Add known amounts of calibration stock solution to eluent in 10-mL volumetric flasks and dilute to the mark. Use serial dilutions as needed to obtain analyte concentrations in the range 0.02 to 7 µg/mL. b. Analyze with samples and blanks (steps 12 and 13). c. Prepare calibration graph (peak area vs. µg analyte). NIOSH Manual of Analytical Methods (NMAM), Fourth Edition, 8/15/94