Page:NIOSH Manual of Analytical Methods - 1451.pdf/2

 METHYL CELLOSOLVE ACETATE: METHOD 1451, dated 15 August 1994 - Page 2 of 3 REAGENTS: 1. 2.

3. 4. 5.

EQUIPMENT:

Methyl cellosolve acetate, ACS reagent grade. Eluent: carbon disulfide*, chromatographic grade, with 0.1% v/v undecane (optional internal standard). Helium, purified. Hydrogen, prepurified. Air, filtered, compressed.



1.

See SPECIAL PRECAUTIONS 2. 3. 4. 5. 6. 7.

Sampler: glass tube, 7 cm long, 6-mm OD, 4-m ID, flame-sealed ends with plastic caps, containing two sections of 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 at 1 L/min must be less than 3.4 kPa. Tubes are commercially available. Personal sampling pump, 0.01 to 0.2 L/min, with flexible connecting tubing. Gas chromatograph equipped with FID, integrator and column (page 1451-1). Vials, 2-mL, glass, PTFE-lined crimp caps. Syringe, 10 µL, readable to 0.1 µL. Pipet, 1-mL, readable to 0.1 mL. Volumetric flasks, 10-mL.

SPECIAL PRECAUTIONS: Carbon disulfide is toxic and a serious fire and explosion hazard (flash point = -30 °C); work with it only in a hood.

SAMPLING: 1. 2. 3. 4.

Calibrate each personal sampling pump with a representative sampler in line. Break 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 0.2 to 20 L. Cap the samplers 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 six working standards over the range of 10 to 4500 µg per sample. a. Add known amounts of methyl cellosolve acetate to 1 mL eluent in sample vials. b. Analyze together with samples and blanks (steps 11 and 12). c. Prepare calibration graph (peak area or ratio of peak area of analyte to peak area of internal standard vs. µg methyl cellosolve acetate). 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