Page:NIOSH Manual of Analytical Methods - 2530.pdf/2

 DIPHENYL: METHOD 2530, Issue 2, dated 15 August 1994 - Page 2 of 4 REAGENTS: 1. 2. 3. 4. 5.

6.

7.

EQUIPMENT:

Acetone, reagent grade.* Hexane, reagent grade.* Carbon tetrachloride (CCl 4), reagent grade.* Diphenyl, reagent grade. Calibration stock solution, 1.2 mg/mL. Dilute an accurately weighed 120-mg portion of diphenyl to 100 mL with carbon tetrachloride. Desorption efficiency (DE) stock solution, 12 mg/mL. Dilute an accurately weighed 120-mg portion of diphenyl to 10 mL with hexane. Nitrogen, purified.



1.

See SPECIAL PRECAUTIONS.

2. 3. 4. 5. 6. 7. 8.

SPECIAL PRECAUTIONS: Hexane (flash point = -22 °C) and acetone (flash point = -18 °C) are highly flammable and carbon tetrachloride is highly toxic. Prepare sorbent, samples, and standards in well-ventilated hood.

3. 4.

Sampler: glass tube, 6 cm long, 6-mm OD, 4mm ID, containing two sections of cleaned 35/60 mesh Tenax GC (front = 20 mg; back = 10 mg), separated by 2-mm urethane foam plug. A silylated glass wool plug is placed at both ends. Pressure drop across the tube at 0.5 L/min must be less than 3.4 kPa. Cleaned Tenax GC Tubes are commercially available. NOTE: Clean bulk Tenax GC by placing it in sintered glass filter fitted to large vacuum flask. Add volume of acetone equal to twice that of sorbent and mix, then remove acetone by filtration. Repeat washing six times. Dry sorbent at 120 °C under vacuum for 4 h. Personal sampling pump, 0.01 to 0.5 L/min, with flexible connecting tubing. Gas chromatograph, FID, integrator, and column (see page 2530-1). Vials, 2-mL, PTFE-lined caps. Syringe, 10-µL, readable to 0.1 µL. Volumetric flasks, 10- and 100-mL. Pipets, 1-mL, and other convenient sizes. Balance, readable to 0.1 mg.

SAMPLING: 1.

Calibrate each personal sampling pump with a representative sampler in line. 2. Break the ends of the sampler tube immediately before sampling. Attach sampler to personal sampling pump with flexible tubing. Sample at an accurately known flow rate between 0.01 and 0.5 L/min for a total sample size of 15 to 30 L. 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. Add 1.0 mL CCl 4 to each vial. Cap each vial. Allow to stand 15 min with occasional agitation. NOTE: Fine particles of Tenax tend to plug an autosampler syringe. For use with autosampler, transfer supernatant solutions to autosampler vials.

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