Ten NIOSH analytical methods - hafnium.
Cincinnati, OH: U.S. Department of Health, Education, and Welfare, Public Health Service, Centers for Disease Control, National Institute for Occupational Safety and Health, 1979 Apr; :1-25
The NIOSH validated method for the determination of hafnium (7440586) (Hf) is described. Ninety liters of air (flow rate at 1.5 to 2.0 liters per minute) is drawn through a mixed cellulose ester membrane filter to trap Hf. The sample and filter are digested successively with 3 milliliters (ml) of concentrated nitric-acid twice, 3ml of nitric-acid plus 5 drops of concentrated perchloric- acid, 1ml of nitric-acid plus 5ml of 5 percent hydrofluoric-acid, evaporating to dryness between each step except the last which is evaporated until a droplet of solution remains. Three to 5ml of 5 percent Hf were added. After cooling, the solution is added to a 10ml volumetric flask and filled to the mark with 5 percent hydrofluoric-acid. The solution is analyzed by emission spectroscopy at the wavelength of 264.1 nanometers. The concentration of Hf is determined by comparison with a calibration curve obtained by analyzing standards having concentrations equal to meter (mg/m3). The method is useful for determining Hf concentrations of 0.26 to 1.05mg/m3 with a standard deviation of 0.043mg/m3. A detection limit has not been established.
NIOSH-Author; NIOSH-Analytical-Method; Analytical-Method; Standards; Sampling; Standards-Completion-Program; SCP; Set-7; Spectrographic-analysis; Heavy-metals
NTIS Accession No.
National Institute for Occupational Safety and Health