National Institute for Occupational Safety and Health

“ Clean the tem plate in pre paration for the next w ipe sam ple using water or a wipe. A disposable template may also be used. 8. Rem ove gloves and discard. Clean gloves should be worn for each new sample. 9. Field blanks: 10% of samples, at least three per batch. Remove unexposed wipes from packaging and place into sample containers. The field blanks should be collected at the beginning, middle, and end of sampling.
SAMPLE PREPARATION: 10. Transfer the samples and blanks to clean beakers. 11. Add 20 mL concentrated nitric acid and 1 mL concentrated perchloric acid. ”

“ Nitric and perchloric acids are strong oxidizers and extremely corrosive. Perform all perchloric acid digestions in a perchloric acid hood. When working with acids use gloves and avoid inhalation or contact with skin or clothing.
SAMPLING: [3] 1. W earing a clean pair of powder-less, plastic gloves, place the template over the area to be sampled and secure it. If the area to be sampled is in a confined area and a template cannot be used, measure the sampling area, and delineate the area to be sampled with mask ing tape. 2. Re m ove a wipe from its pac kage, and u nfold it. 3. ”

“ Analyze a standard for every six samples. 22. Check recoveries with at least two spiked media blanks per ten samples.
MEASUREMENT: 23. Set spec trome ter to conditions spe cified by manufac turer. 24. Analyze standards and samples. NOTE: If the va lues for the sam ples are a bove the rang e of the standa rds, dilute the solutions w ith dilution acid, re-analyze and apply the appropriate dilution factor in the calculations. ”