Page:NIOSH Manual of Analytical Methods - 5023.pdf/2

 COAL TAR PITCH VOLATILES: METHOD 5023, Issue 2, dated 15 August 1993 - Page 2 of 3 EQUIPMENT:

REAGENTS: 1. 2. 3. 4.



Solvent, Benzene,* cyclohexane or other solvent, reagent grade. Dichromic acid cleaning solution. Acetone, reagent grade. Hexane.

See SPECIAL PRECAUTIONS.

1. Sampler: PTFE laminated membrane filter, 2-µm pore size, 37-mm diameter (Zefluor, Membrana Inc., Pleasanton, CA; Gelman Sciences, or equivalent) backed by a gasket 37-mm OD, 32-mm ID, cut from a cellulose support pad (SKC, Inc. or equivalent) in plastic filter holder. 2. Personal sampling pump, 1 to 4 L/min, with flexible connecting tubing. 3. Ultrasonic bath. 4. Microbalance, readable to 1 µg, with NIST Class M weights. 5. Environmental chamber for balance, e.g., 20 °C ± 0.3 °C and 50% ± 5% relative humidity. 6. Weighing cups, PTFE, 2-mL, approximate tare weight 60 mg, in metal rack. 7. Vacuum oven. NOTE: Keep the interior of the vacuum oven dust-free for maximum sensitivity, reproducibility, and accuracy. 8. Forceps. 9. Test tubes, PTFE-lined screw caps, 13-mm x 100-mm.* 10. Filter, 0.5-µm (Millex-SR, Millipore Corp., Bedford, MA or equivalent). 11. Pipets, 1- and 5-mL* with bulb.

Rinse with distilled water, acetone, and hexane; dry.

SPECIAL PRECAUTIONS: Benzene and coal tar pitch volatiles are suspect carcinogens [1,2,3,4].

SAMPLING: 1. 2. 3.

Calibrate each personal sampling pump with a representative sampler in line. Sample at an accurately known flow rate between 1 and 4 L/min for a total sample volume of 500 to 2400 L. Do not exceed a filter loading of ca. 2 mg total particulate. Replace caps in cassette and ship to laboratory.

SAMPLE PREPARATION: 4.

5. 6.

Transfer filter carefully using forceps to test tube. Add 5.0 mL solvent via pipet. Cap the tube. NOTE 1: Cyclohexane is recommended as solvent because of the carcinogenic potential of benzene [2]. NOTE 2: This extraction is also applicable to bulk samples (ground and sieved to ca. 250 µm). Extract 250 mg bulk sample with 5.0 mL solvent. Place tube upright in beaker containing water to the same level as the liquid in the tube. Place beaker and tube in ultrasonic bath. Ultrasonicate for 20 min. Filter solution through a 0.5-µm filter into a clean, preweighed weighing cup. Discard the filter. NIOSH Manual of Analytical Methods (NMAM), Fourth Edition, 8/15/93