National Institute for Occupational Safety and Health

“ Calibrate daily with at least six working standards over the range 3 to 1200 μg F per sample. a. Add known amounts of calibration stock solution to 25 mL TISAB and 5 mL 20% NaOH (particulate fluoride) or 25 mL TISAB (gaseous fluoride) in 100-mL beakers. b. Adjust pH to 5.5 ± 0.2 with 1:1 HCl. c. Transfer to 50-mL volumetric flasks. Dilute to the mark with deionized water. NOTE: Working standards are stable at least one month in polyethylene bottles at 4 °C. d. ”

“ NIOSH/OSHA Occupational Health Guidelines for Chemical Hazards, U.S. Department of Health and Human Services Publ. (NIOSH) 81-123 (1981) , available as GPO Stock #17-033-00337-8 from Superintendent of Documents, Washington, DC 20402. ”

“ Calibrate each personal sampling pump with a representative sampler in line. Sample at an accurately known flow rate between 1 and 2 L/min for a total sample size of 12 to 800 L. Do not exceed 2 mg total dust loading on the filter. Pack securely for shipment.
SAMPLE PREPARATION: 4.
Cellulose ester membrane filter (particulate fluoride) . NOTE: Water-soluble particulate fluorides may be extracted by the procedure for gaseous fluorides. Insoluble particles require fusion. a. Transfer the membrane filter to a crucible containing 5 mL 20% NaOH. b. Evaporate to dryness. c. ”