Page:NIOSH Manual of Analytical Methods - 500124-D.pdf/2

 2,4-D AND 2,4,5-T: METHOD 5001, Issue 2, dated 15 August 1994 - Page 2 of 4 EQUIPMENT:

REAGENTS: 1. 2. 3. 4.

2,4-dichlorophenoxyacetic acid.* 2,4,5-trichlorophenoxyacetic acid.* Methanol, HPLC grade. LC eluent: a. 2,4-D: 0.001 N NaClO 4 and 0.001 N Na 2B4O 7. Add 0.122 g NaClO 4 and 0.381 g Na 2B4O 7⋅10H 2O to a 1-L volumetric flask. Bring to volume with distilled water. Mix, filter and de-gas the solution. b. 2,4,5-T: 0.003 M NaClO 4 and 0.001 M Na 2B4O 7⋅10H 2O. Add 0.366 g NaClO 4 and 0.381 g Na 2B4O 7⋅10H 2O to a 1-L volumetric flask. Bring to volume with distilled water. Mix, filter and de-gas the solution. 5. Compressed, filtered air or nitrogen for drying syringes. 6. Ethanol, absolute. 7. Acetone. 8. Calibration stock solution, 400 µg/mL. Dissolve 0.400 g 2,4-D or 2,4,5-T in methanol and dilute to 1 L with methanol. 9. Recovery stock solution: a. Dissolve 0.248 g 2,4-D in ethanol. Dilute to 10 mL with ethanol. b. Dissolve 0.250 g 2,4,5-T, triethylamine salt, in acetone (or 0.250 g 2,4,5-T in methanol). Dilute to 10 mL with acetone. NOTE: Use the same form (e.g., acid or salt) of 2,4,5-T as in the air sample. Recovery may vary with the chemical form.

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Wash all glassware with detergent, thoroughly rinse with tap water and distilled water.

See SPECIAL PRECAUTIONS.

SAMPLING: 1.

1. Sampler: filter, glass fiber, binderless, in a 37-mm polystyrene two-piece cassette filter holder (Gelman type AE or equivalent). 2. Personal sampling pump, 1 to 3 L/min, with flexible connecting tubing. 3. High pressure liquid chromatograph, UV detector at 284 nm (2,4-D) and 289 nm (2,4,5-T), integrator and column (page 5001-1). 4. Filter, PTFE, 5-µm, 13-mm diameter in Swinny stainless (13-mm) filter holder. 5. Tweezers. 6. Syringes, 20-mL luer-lock.* 7. Vials, glass, 20-mL.* 8. Volumetric flasks, convenient sizes for preparing standard solutions.*

SPECIAL PRECAUTIONS: 2,4-D and 2,4,5-T are suspected animal carcinogens [4]. 2,3,7,8-Tetrachlorodibenzo-1,4-dioxin has been identified as an impurity in 2,4,5-T. Avoid any contact with these substances.

Calibrate each personal sampling pump with a representative filter in line. Sample at an accurately known flow rate between 1 and 3 L/min for a total sample size of 15 to 200 L. Do not exceed a total dust loading of 2 mg on the filter. Obtain information on the chemical form of the analyte (i.e., ester, salt or free acid) likely to be present in the air sample.

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