DIBUTYL PHOSPHATE: METHOD 5017, Issue 2, dated 15 August 1994 - Page 2 of 3
REAGENTS: 1. 2. 3.
4. 5. 6. 7.
EQUIPMENT:
Dibutyl phosphate,* purified 99%, according to Ref. [3]. Eluent: Acetonitrile, reagent grade, containing 0.1% (v/v) tributyl phosphate internal standard. Calibration stock solution, 45 mg/mL. Dissolve 0.45 g purified dibutyl phosphate in 10 mL acetonitrile. N,O-bis(trimethylsilyl)trifluoroacetamide (BSTFA), reagent grade. Helium, purified. Hydrogen, prepurified. Air, filtered, compressed.
See SPECIAL PRECAUTIONS.
1. Sampler: PTFE membrane filter, 1-µm, (Millipore FA or equivalent), 37-mm diameter in a two-piece polystyrene cassette filter holder. 2. Personal sampling pump, 1 to 3 L/min, with flexible connecting tubing. 3. Jars, squat-form, 60-mL, with PTFE film gaskets, and screw caps. 4. Vial, 2-mL, with PTFE-lined caps. 5. Gas chromatograph with phosphorus FPD, integrator, and column (page 5017-1). 6. Syringes, 5-, 10-, and 25-µL, for making standard solutions and GC injections. 7. Volumetric flasks, 10- and 100-mL. 8. Pipets, 1- and 5-mL. 9. Tweezers.
SPECIAL PRECAUTIONS: Dibutyl phosphate is toxic if inhaled or comes in contact with the eyes or skin [3]. Sample preparations should be SAMPLING: conducted in a hood. 1.
2.
Calibrate each personal sampling pump with a representative sampler in line. 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 50 to 250 L.
SAMPLE PREPARATION: 3. 4. 5. 6.
Using tweezers, carefully transfer the filter to a 60-mL jar. Pipet 5.0 mL eluent into each jar. Cap the jar. Allow to stand 30 min with occasional agitation. Transfer 1.0 mL of the extract to a 2-mL vial. Add 100 µL BSTFA. Cap the vial, shake thoroughly, and let stand 30 min.
CALIBRATION AND QUALITY CONTROL: 7.
8.
Calibrate daily with at least six working standards over the range 0.1 to 2 mg dibutyl phosphate per sample. a. Add known amounts of calibration stock solution to eluent in 10-mL volumetric flasks and dilute to the mark. b. Analyze together with samples and blanks (steps 9 and 10). c. Prepare calibration graph (ratio of peak area of dibutyl phosphate to peak area of internal standard vs. mg dibutyl phosphate). Analyze three quality control blind spikes and three analyst spikes to ensure that the calibration graph is in control.
NIOSH Manual of Analytical Methods (NMAM), Fourth Edition, 8/15/94
