NICKEL CARBONYL: METHOD 6007, Issue 2, dated 15 August 1994 - Page 2 of 4 REAGENTS: 1. 2. 3. 4.
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EQUIPMENT:
Water, double-distilled (or deionized). Nitric acid, 70% (w/v) HNO 3, redistilled in glass. Nitric acid, 3% (w/v) HNO 3. Add 31 mL 70% HNO 3 to distilled water. Dilute to 1 L. Nickel stock solution, 1000 µg Ni/mL. Dissolve 1.000 g pure Ni metal in minimum volume 70% HNO 3. Dilute to 1 L with 3% HNO 3. Commercially available. Calibration stock solution, 50 µg Ni/mL. Dilute 0.500 mL nickel stock solution (1000 µg/mL) to 10 mL in a volumetric flask with 3% HNO 3. Store in a polyethylene bottle. Prepare fresh weekly. Argon, high-purity purge gas in cylinder with a two-stage regulator. NOTE: Nitrogen cannot be used as purge gas because of the formation of UV-absorbing cyanogen. Charcoal, acid-washed, activated. Acid-wash a sufficient quantity of coconut-based charcoal having an initial blank value of less than 0.02 µg Ni/200 mg, by soaking overnight in 3% nitric acid. Rinse several times with distilled water. Pour off excess water, cover with a watchglass, and activate by heating at 600 °C for 1.5 hrs in still air.
1. Sampler: a. Prefilter: 37-mm, 0.8-µm cellulose ester filter and cellulose backup pad in a plastic filter holder. b. Glass tube, 8 cm long, 6-mm OD, 4-mm ID, flame-sealed ends with plastic caps, containing two sections of 20/40 mesh acid-washed activated (600 °C) coconut shell charcoal (front = 120 mg; back = 60 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 airflow must be less than 3.4 kPa. NOTE: The prefilter must be used when particulate nickel is present in the air to be sampled. Connect prefilter to sorbent tube with a short section of plastic tubing. 2. Personal sampling pump, 0.05 to 0.2 L/min, with flexible connecting tubing. 3. File, triangular. 4. Atomic absorption spectrophotometer equipped with: a. Heated graphite atomizing rod, tube or furnace (either non-pyrolitic or pyrolitic; better sensitivity with pyrolitic). NOTE: Reproducible control of times and temperatures during dry, char, and atomize cycles is essential; minimum atomization temperature 2700 °C. b. Readout device (recorder or digital peak height or peak area analyzer). c. Pipetting system (automatic or manual, 5to 50-µL, as appropriate to atomizer size). d. Background correction, e.g., D 2 or H 2 lamp or non-absorbing line (231.5 nm for the 232 nm Ni line). e. Hollow cathode lamp for nickel. 5. Vials, 2-mL, with plastic-lined screw caps.* 6. Pipet, TD, 1-mL.* 7. Ultrasonic water bath. 8. Volumetric flasks, 10-mL and 1-L.* 9. Bottles, polyethylene, 20-mL. 10. Syringe, 25-µL, readable to 0.1 µL.
- Soak new glassware 1 h in hot, conc. nitric
acid followed by thorough rinsing with distilled water. After each use, wash glassware with, in order, detergent solution, tap water, 3% nitric acid (soak ≥4 h) and distilled water.
NIOSH Manual of Analytical Methods (NMAM), Fourth Edition, 8/15/94
