Page:NIOSH Manual of Analytical Methods - 7504.pdf/2

 VANADIUM OXIDES: METHOD 7504, Issue 2, dated 15 August 1994 - Page 2 of 10 REAGENTS: 1.

2. 3. 4. 5. 6.

EQUIPMENT:

V2O 5, V 2O 3 or NH 4VO 3 (≥99%). Grind in freezer mill. Sieve through 10-µm sieve in isopropanol (for V 2O 3 or NH 4VO 3) or acetonitrile (for V 2O 5). Dry at 110 °C for one hour. Store in desiccator. Tetrahydrofuran (THF), reagent grade.* Isopropanol, reagent grade. Acetonitrile, reagent grade. Glue or tape for securing silver filters to XRD holders. Desiccant.


 * See SPECIAL PRECAUTIONS.

1. Sampler: a. Filter: 37-mm diameter, 5.0-µm pore size, polyvinyl chloride filter supported with backup pad in a two-piece, 37-mm cassette filter holder (preferably, conductive) held together by tape or cellulose shrink band. NOTE: Test PVC filter for THF digestion (see Step 4). b. Cyclone: 10-mm nylon or Higgins-Dewell (HD), or equivalent. c. Sampling head holder: Holder must keep the cassette, cyclone, and coupler together rigidly so that air enters only at the cyclone inlet. 2. Bulk sampler: PVC membrane filter, 37-mm, 5-µm pore size in two-piece filter cassette. Sample closed face at 3 L/min. 3. Sampling pumps: HD cyclone, 2.2 L/min; nylon cyclone, 1.7 L/min; and bulk sampler, 3 L/min. 4. Filters, silver membrane, 25-mm diameter, 0.45-µm pore size (Osmonics, Inc., Nuclepore, Poretics, or equivalent). 5. X-ray powder diffractometer with copper target X-ray tube, graphite monochromator, and scintillation detector. 6. Reference specimen (mica, Arkansas stone or other stable standard. Source: Gem Dugout, State College, PA, 16801) for data normalization. 7. Filtration apparatus and side arm vacuum flask, with 25-mm filter holders. 8. Sieve, 10-µm, for wet-sieving. 9. Centrifuge tubes, wide-mouth, 40-mL. 10. Ultrasonic bath or probe. 11. Analytical balance (0.01 mg). 12. Magnetic stirrer with thermally-insulated top. 13. Bottles, reagent, 1-L, with ground glass stoppers. 14. Drying oven. 15. Polyethylene wash bottle. 16. Desiccator. 17. Pipets, TD, 2- to 25-mL.

SPECIAL PRECAUTIONS: THF is extremely flammable and should be used in a fume hood.

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