Page:NIOSH Manual of Analytical Methods - 5020.pdf/2

 DIBUTYL PHTHALATE and DI(2-ETHYLHEXYL) PHTHALATE: METHOD 5020, Issue 2, dated 15 August 1992 - Page 2 of 4

REAGENTS: 1.

2. 3.

4. 5. 6.

EQUIPMENT:

Eluent: Carbon disulfide*, chromatographic quality, containing 0.05% (w/v) heneicosane, tetradecane, tricosane, di(2-ethylhexyl)adipate or other suitable internal standard. Analytes: dibutyl phthalate and di(2-ethylhexyl) phthalate. Recovery stock solution, 10 mg/mL. Dissolve 0.1 g of each analyte in CS 2 to make 10 mL solution. Helium, purified. Hydrogen, prepurified. Air, filtered, compressed.

See SPECIAL PRECAUTIONS.

1. Sampler: mixed cellulose ester membrane filter, 0.8-mm pore size, 37-mm diameter, in two-piece cassette filter holder with backup pad. 2. Personal sampling pump, 1 to 3 L/min, with flexible connecting tubing. 3. Gas chromatograph, FID, integrator, and column (page 5020-1). 4. Vials, glass, 5-mL, PTFE-lined caps. 5. Syringes, 1- and 10-µL and other convenient sizes for making standards. 6. Volumetric flasks, 10-mL. 7. Pipet, volumetric, 2-mL, with pipet bulb. 8. Ultrasonic bath. 9. Tweezers.

SPECIAL PRECAUTIONS: Carbon disulfide is toxic and a dangerous 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. Remove cassette plugs immediately before sampling. Attach sampler to personal sampling pump with flexible tubing. Sample at an accurately known flow rate between 1 and 3 L/min for a total sample size of 10 to 200 L. Cap the samplers with the cassette plugs and pack securely for shipment.

SAMPLE PREPARATION: 5. 6. 7.

Open the cassette and carefully transfer the filter with tweezers to a 5-mL vial. Discard the backup pad. Add 2.0 mL eluent to each vial and attach caps. Agitate for 30 min in an ultrasonic bath.

CALIBRATION AND QUALITY CONTROL: 8.

9.

Calibrate daily with at least five working standards over the range 0.1 to 0.5 mg analyte per sample. a. Add known amounts of analyte (or standard solution of analyte in CS 2) 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 (ratio of peak area of aanalyte to peak area of internal standard vs. mg analyte). Determine recovery (R) at least once for each lot of filters used for sampling in the calibration range. Prepare three filters at each of five levels plus three media blanks. a. Deposit a known amount (1 to 50 µL) of recovery stock solution onto the filter. Allow filters NIOSH Manual of Analytical Methods (NMAM), Fourth Edition, 8/15/92