National Institute for Occupational Safety and Health

“ Protect from light during transfer and desorption. Under very dim or red light, open cassette and transfer the silver filter with forceps to amber bottle. Add 3 mL 6 m M Na 2S2O 3 and cap. NOTE: Prefilter may be analyzed for particulate halides, or discarded. Allow samples to stand a minimum of 10 min with occasional swirling. NOTE: Once desorbed, samples are no longer photosensitive. Uncap the sample bottles and add 7 mL deionized water for a total solution volume of 10 mL. Pour sample into 10-mL plastic syringe for manual injection or into autosampler vials. ”

“ Some lots of silver membrane filters contain excessively high chloride background levels. Please screen before field use.
SPECIAL PRECAUTIONS: Sulfuric acid is extremely corrosive to skin, eyes, and mucous membranes. Wear protective clothing. Handle in a fume hood.
SAMPLING: 1. 2. 3. 4.
Calibrate each personal sampling pump with a representative sampler in line. Attach sampler to personal sampling pump with flexible tubing. Sample at an accurately known flow rate between 0.3 and 1 L/min for a total sample size of 8 to 360 L for bromine or 2 to 90 L for chlorine. ”

“ Calibrate daily with at least six working standards covering the range of 0.2 to 15 μg bromide and/or 0.05 to 5 μg chloride per mL of sample. a. Add known aliquots of calibration stock solution to deionized water in 10-mL volumetric flasks and dilute to the mark with deionized water. b. Prepare fresh working standards biweekly. c. Analyze working standards together with samples and blanks (steps 11 through 13) . d. Prepare a calibration graph (peak height vs. μg of anion per sample) . ”