Page:NIOSH Manual of Analytical Methods - 2529.pdf/2

 FURFURAL: METHOD 2529, Issue 2, dated 15 August 1994 - Page 2 of 4 REAGENTS:

EQUIPMENT:

1. Toluene, chromatographic quality. 2. 2-(Hydroxymethyl)piperidine. Recrystallize several times from isooctane until there is one major peak (>95% of area) by GC analysis. Store in desiccator. 3. Amberlite XAD-2 (Rohm and Haas) or equivalent. Extract 4 h in Soxhlet with 50/50 (v/v) acetone/methylene chloride. Replace with fresh solvent and repeat. Vacuum dry overnight. 4. Furfural,* freshly distilled under N 2 to remove impurities. Store at 0 °C. 5. Calibration stock solution, 100 µg/µL. Add 1 g furfural to toluene and dilute to 10 mL. Prepare in duplicate. 6. Furfural oxazolidine (see APPENDIX) stock solution, 2.5 mg/mL. Add 25 mg to toluene and dilute to 10 mL. 7. Water, deionized, then distilled. 8. Hydrogen, prepurified. 9. Air, filtered. 10. Helium, purified.



See SPECIAL PRECAUTIONS.

1. Sampler: glass tube, 10 cm x 4-mm ID, flame-sealed, with plastic caps, containing a 120-mg front section and a 60-mg back-up section of the 2-(hydroxymethyl)piperidinecoated XAD-2 (see APPENDIX) with flame-sealed ends. Sorbent sections are retained and separated by small plugs of silanized glass wool. Pressure drop across the tube at 0.10 L/min airflow must be less than 756 kPa. Tubes are commercially available (Supelco ORBO 23 or equivalent). 2. Personal sampling pump, 0.01 to 0.05 L/min, with flexible connecting tubing. 3. Gas chromatograph, flame ionization detector, integrator and column (page 2529-1). 4. Ultrasonic bath. 5. Vials, glass, 4-mL, with septum and plastic screw caps. 6. Flasks, volumetric, 10-, 25-, and 50-mL. 7. Pipets, volumetric, 1-, 2-, and 10-mL with pipet bulb. 8. Pipets, disposable, 2-mL. 9. Syringes, 10-µL (readable to 0.1 µL), 25-, and 50-µL. 10. File. 11. Beakers, 50-mL. 12. Magnetic stirrer. 13. Flasks, round-bottomed, 100-mL. 14. Soxhlet extraction apparatus. 15. Vacuum oven. 16. Distillation apparatus.

SPECIAL PRECAUTIONS: Furfural can irritate the mucous membranes and act on the central nervous system [3,4]. Work with this compound only in a well-ventilated hood. SAMPLING: 1. 2. 3.

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 1 to 12 L. NOTE: Furfural reacts with 2-(hydroxymethyl)piperidine to form a derivative during sampling. Sampling rate is limited by the speed of this reaction; rates above 0.05 L/min may cause breakthrough owing to incomplete reaction.

SAMPLE PREPARATION: 4. 5.

Score each sampler with a file in back of the rear sorbent section. Break sampler at score line. Remove and place rear glass wool plug and rear sorbent section in a vial. NIOSH Manual of Analytical Methods (NMAM), Fourth Edition, 8/15/94