National Institute for Occupational Safety and Health

“ Interactions between analytes may reduce breakthrough volumes and affect desorption efficiencies. Naphthalene, originally validated in S292 [4] , failed to meet acceptable desorption efficiency recovery and storage stability criteria at the levels evaluated in this study. However, the application of this method to naphthalene levels at or near the REL/PEL continues to meet acceptable recovery criteria. Styrene failed to meet acceptable recovery criteria at the two lowest levels evaluated in this study (highest level to meet the criteria was 181 μg/sample) . ”

“ Under conditions of high humidity, the breakthrough volumes may be reduced. Other volatile organic compounds such as alcohols, ketones, ethers, and halogenated hydrocarbons are potential analytical interferences. ”

“ Prepare c alibration graph (pe ak area of analyte vs. μg analyte per sam ple) .
NIOSH Manual of Analytical Methods (NMAM) , Fourth Edition HYD RO CAR BO NS, AR OM ATIC : MET HO D 150 1, Issue 3, dated 15 M arch 200 3 - page 3 of 7 9. Determine desorption efficiency (DE) at least once for each batch of charcoal used for sampling in the calibra tion ran ge (s tep 8) . a. Prepare three tubes at each of five levels plus three media blanks. b. Inject a known amount of DE stock solution (5 to 25 μL) directly onto front sorbent section of each charcoal tube with a microliter syringe. c. ”