Page:NIOSH Manual of Analytical Methods - 2508.pdf/2

 ISOPHORONE: METHOD 2508, Issue 2, dated 15 August 1994 - Page 2 of 3 REAGENTS: 1. 2. 3. 4. 5.

EQUIPMENT:

Carbon disulfide, chromatographic grade.* Isophorone.* Nitrogen, prepurified. Hydrogen, prepurified. Air, filtered.



See SPECIAL PRECAUTIONS.

1. Sampler: glass tube, 7 cm long, 6-mm OD, 4mm ID, flame-sealed ends, containing two sections of 20/40 mesh petroleum-based charcoal (100 mg front/50 mg back) separated by a 2-mm urethane foam plug. A silylated glass wool plug precedes the front section and a 3-mm urethane foam plug follows the back section. Pressure drop across the tube at 1 L/min must be less than 3.4 kPa. Tubes are commercially available. 2. Personal sampling pump, 0.01 to 1 L/min, with flexible connecting tubing. 3. Gas chromatograph, FID, integrator and column (page 2508-1). 4. Vials, 2-mL, PTFE-lined caps. 5. Syringe, 10-µL, readable to 0.1 µL. 6. Volumetric flasks, 10-mL. 7. Pipet, 1-mL, with pipet bulb.

SPECIAL PRECAUTIONS: CS 2 is toxic and acute fire and explosion hazard (flash point = -30 °C). Work with it only in a hood. Isophorone is a lachymator [3]; work with it should be done in a hood and caution should be taken while it is being used.

SAMPLING: 1. 2. 3. 4.

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 1.0 L/min for a total sample size of 2 to 25 L. Cap the samplers with plastic (not rubber) caps and 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 CS 2 to each vial. Attach crimp cap to each vial. Allow to stand 30 min with occasional agitation.

CALIBRATION AND QUALITY CONTROL: 8.

Calibrate daily with at least six working standards over the range 0.02 to 10 mg isophorone per sample. a. Add known amounts of isophorone to CS 2 in 10-mL volumetric flasks and dilute to the mark. b. Analyze together with samples and blanks (steps 11 and 12). c. Prepare calibration graph (peak area vs. mg isophorone).

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