ALUMINUM and compounds, as Al
Al
MW:
26.98 (Al); 101.96 (Al203)
CAS: 7429-90-5 (Al); 1344-28-1 (Al203)
METHOD: 7013, Issue 2
RTECS: BD0330000 BD1200000
EVALUATION: PARTIAL
OSHA : no PEL NIOSH: see table 1 ACGIH: see table 1
7013
Issue 1: 15 February 1984 Issue 2: 15 August 1994
PROPERTIES: ductile metal; valence 3; MP 660 °C
SYNONYMS: vary depending upon the compound; alumina (Al 2O 3)
SAMPLING SAMPLER:
FILTER (0.8-µm cellulose ester membrane)
MEASUREMENT TECHNIQUE:
ATOMIC ABSORPTION, FLAME
ANALYTE:
aluminum
FLOW RATE: 1 to 3 L/min ASHING: VOL-MIN: -MAX:
10 L @ 5 mg/m 3 400 L
SHIPMENT:
routine
conc. HNO 3, 6 mL; 140 °C
FINAL SOLUTION:
10% HNO 3, 10 mL 1000 µg/mL Cs
FLAME:
nitrous oxide-acetylene, reducing 309.3 nm
SAMPLE STABILITY:
stable
WAVELENGTH:
BLANKS:
2 to 10 field blanks per set
BACKGROUND CORRECTION: none used CALIBRATION:
Al3+ in 10% HNO 3
RANGE:
50 to 5000 µg per sample [1]
ACCURACY ESTIMATED LOD: 2 µg per sample [2] RANGE STUDIED:
not studied
BIAS:
none identified
ˆ ): OVERALL PRECISION (S rT
not evaluated
ACCURACY:
not evaluated
PRECISION (Sr):
0.03 [1,2]
APPLICABILITY: The working range is 0.5 to 10 mg/m 3 for a 100-L sample. This is an elemental analysis, not compound specific. Verify that the types of compounds in the samples are soluble with this ashing procedure. Aliquots of the samp les can be analyzed separately for approximately four additional metals.
INTERFERENCES: Cesium at 1000 µg/mL controls ionization in the nitrous oxide-acetylene flame [3]. Iron and HCl at greater than 0.2% (w/w) decrease the sensitivity. Vanadium or H 2SO 4 require 1% (w/w) La as a releasing agent [4].
OTHER METHODS: This is Method P&CAM 173 for Al [1] in a revised format. Method 7300 (ICP-AES) is an alternate analytical method.
NIOSH Manual of Analytical Methods (NMAM), Fourth Edition, 8/15/94 ALUMINUM and compounds, as Al: METHOD 7013, Issue 2, dated 15 August 1994 - Page 2 of 3 REAGENTS:
EQUIPMENT:
1. Nitric acid, conc. 2. Nitric acid, 10% (v/v). Add 100 mL conc. HNO 3 to 500 mL water; dilute to 1 L. 3. Calibration stock solution, 1000 µg Al/mL. Commercially available or dissolve 1.000 g Al wire in minimum volume of (1+1) HCl using small drop of Hg as catalyst. Dilute to 1 L with 1% (v/v) HCl. 4. Cs solution, 50 mg/mL. Dissolve 73.40 g CsNO 3 in 100 mL water; dilute to 1 L. 5. Nitrous oxide. 6. Acetylene. 7. Distilled or deionized water.
1. Sampler: cellulose ester membrane filter, 0.8-µm pore size, 37-mm diameter; in cassette filter holder. 2. Personal sampling pump, 1 to 3 L/min, with flexible connecting tubing. 3. Atomic absorption spectrophotometer with a nitrous oxide-acetylene burner head and aluminum hollow cathode lamp. 4. Regulators, two-stage, for N 2O and acetylene. 5. Beakers, Phillips, 125-mL, or Griffin, 50-mL, with watchglass covers.* 6. Volumetric flasks, 10- and 100-mL.* 7. Micropipets, 5 to 500 µL.* 8. Hotplate, surface temperature 100 to 140 °C.
Clean with conc. nitric acid and rinse thoroughly with distilled or deionized water before use.
SPECIAL PRECAUTIONS: Perform all acid digestions in a fume hood. SAMPLING: 1. 2.
Calibrate each personal sampling pump with a representative sampler in line. Sample at an accurately known flow rate between 1 and 3 L/min for a total sample size of 10 to 400 L. Do not exceed 2 mg total dust loading on the filter.
SAMPLE PREPARATION: NOTE: Alumina (Al 2O 3) will not be dissolved by this procedure. Lithium borate fusion is necessary to dissolve alumina. The following sample preparation gave quantitative recovery for soluble aluminum compounds (see EVALUATION OF METHOD). Steps 4 through 9 of Method 7300 or other quantitative ashing techniques may be substituted, especially if several metals are to be determined on a single filter. 3. Open the cassettes and transfer the samples and blanks to separate clean beakers. 4. Add 6 mL conc. HNO 3 and cover with a watchglass. Start reagent blanks at this point. 5. Heat on hotplate (140 °C) until sample dissolves and a slightly yellow solution is produced. Add acid as needed to completely destroy organic material. 6. When the sample solution is clear, remove watchglass and rinse into the beaker with 10% HNO 3. 7. Place the beakers on a hotplate and allow to go to a small liquid volume (ca. 0.5 mL). 8. When sample is dry, rinse walls of beaker with 3 to 5 mL 10% HNO 3. Reheat for 5 min to dissolve the residue, then allow to air cool. 9. Transfer the solution quantitatively to a 10-mL volumetric flask containing 0.2 mL 50 mg/mL Cs solution. Dilute to volume with 10% HNO 3. NOTE: If vanadium or sulfuric acid are present, add 1% (w/w) La as a releasing agent [1,3].
CALIBRATION AND QUALITY CONTROL: 10.
Add known amounts, covering the range 0 to 500 mg Al per sample, of calibration stock solution to 100-mL volumetric flasks containing 2.0 mL 50 mg/mL Cs solution and dilute to volume with NIOSH Manual of Analytical Methods (NMAM), Fourth Edition, 8/15/94 ALUMINUM and compounds, as Al: METHOD 7013, Issue 2, dated 15 August 1994 - Page 3 of 3
11. 12. 13. 14. 15.
10% HNO 3. Analyze the working standards together with the samples and blanks (steps 16 and 17). Prepare a calibration graph of absorbance vs. solution concentration (µg/mL). Aspirate a standard for every 10 samples to check instrument drift. Check recoveries with at least one spiked media blank per 10 samples. Use method of additions occasionally to check for interferences.
MEASUREMENT: 16. 17.
Set spectrophotometer according to manufacturer's instructions and to conditions on page 7013-1. Aspirate standards and samples. Record absorbance readings. NOTE: If the absorbance values for the samples are above the linear range of the standards, dilute the solutions with 10% HNO 3 and an appropriate amount of the 50 mg/mL Cs solution, reanalyze, and apply the appropriate dilution factor in the calculations.
CALCULATIONS: 18. 19.
Using the measured absorbances, calculate the corresponding concentrations (µg/mL) of aluminum in the sample, C s, and average media blank, C b, from the calibration graph. Using the solution volumes (mL) of the sample, V s, and media blanks, V b, calculate the concentration, C (mg/m 3), of aluminum in the volume of air sampled, V (L):
EVALUATION OF METHOD: Estimated LOD was 2 µg Al per sample [2]. Only the analytical procedure was evaluated for this method. REFERENCES: [1] [2] [3] [4]
NIOSH Manual of Analytical Methods, 2nd ed., V. 5, P&CAM 173, U.S. Department of Health, Education, and Welfare, Publ. (NIOSH) 79-141 (1979). User check, UBTL, NIOSH Seq. #3990-0 (unpublished, November 29, 1983). Winefordner, J. D., Ed., Spectrochemical Methods of Analysis, John Wiley & Sons (1971). Analytical Methods for Atomic Absorption Spectrophotometry , Perkin-Elmer (1976).
METHOD REVISED BY: Mark Millson, NIOSH/DPSE and R. DeLon Hull, Ph.D., NIOSH/DBBS. TABLE 1 - ALUMINUM EXPOSURE LIMITS OSHA mg/m 3 Total Dust Respirable Fraction Pyro powders Welding fumes Soluble salts
no no no no no
PEL PEL PEL PEL PEL
NIOSH mg/m 3
ACGIH mg/m 3
10 5 5 5 2
10 -5 5 2
NIOSH Manual of Analytical Methods (NMAM), Fourth Edition, 8/15/94 ALUMINUM and compounds, as Al: METHOD 7013, Issue 2, dated 15 August 1994 - Page 4 of 3 Alkyls
no PEL
2
2
NIOSH Manual of Analytical Methods (NMAM), Fourth Edition, 8/15/94