Page:NIOSH Manual of Analytical Methods - 1301.pdf/2

 KETONES II: METHOD 1301, Issue 2, dated 15 August 1994 - Page 2 of 5 REAGENTS: 1.

2. 3. 4. 5.

EQUIPMENT:

Eluent: Carbon disulfide* (chromatographic grade) with 1% (v/v) methanol (chromatographic grade). Analytes, reagent grade. Nitrogen, prepurified. Hydrogen, dry. Air, filtered.



See SPECIAL PRECAUTIONS.

1. Sampler: glass tube, 7 cm long, 6-mm OD, 4-mm ID, flame-sealed ends, containing two sections of 20/40 mesh activated (600 °C) coconut shell charcoal (front = 100 mg; back = 50 mg) 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 must be less than 3.4 kPa at the sampling flow rate. Tubes are commercially available. 2. Personal sampling pump, 0.02 to 0.2 L/min, with flexible connecting tubing. 3. Gas chromatograph, FID, integrator and column (page 1301-1). 4. Vials, 2-mL glass, PTFE-lined crimp caps. 5. Syringe, 10-µL, readable to 0.1 µL. 6. Pipet, 1-mL, with pipet bulb. 7. Volumetric flasks, 10-mL.

SPECIAL PRECAUTIONS: Carbon disulfide is toxic and an acute fire and explosion hazard (flash point = -30 °C); all work done with it must be performed in a fume hood.

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 0.2 L/min for a total sample size of 1 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 in separate vials. Discard the glass wool and foam plugs. Add 1.0 mL eluent to each vial. Attach crimp cap to each vial. Allow to stand 30 min with occasional agitation.

CALIBRATION AND QUALITY CONTROL: 8.

9.

Calibrate daily with at least five working standards over the range 0.01 to 0.5 mg camphor; and 0.05 to 5 mg of the other analytes per sample. a. Add known amounts of analyte to eluent 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 analyte). Determine desorption efficiency (DE) at least once for each batch of charcoal used for sampling in the calibration range (step 8). Prepare three tubes at each of five levels plus three media blanks. NIOSH Manual of Analytical Methods (NMAM), Fourth Edition, 8/15/94