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 #3990-0 (unpublished, November 29, 1983).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
