Comparison of three sampling and analytical methods for measuring m-xylene in expired air of exposed humans.
Glaser-RA; Arnold-JE; Shulman-SA
Am Ind Hyg Assoc J 1990 Mar; 51(3):139-150
A comparison of breath sampling methods was made for subjects exposed to 75 parts per million m-xylene (108383) for 4 hours. The sampling was performed in the 240 minutes immediately following exposure. The m-xylene was sampled from the mainstream using charcoal cloth and from the sidestream using Tenax/TA. Alveolar breath was also sampled for m-xylene from six of the subjects using bags. The accuracy of the mixed expired sampling and analytical procedures was evaluated through the collection of carbon-dioxide concentrations of the mixed and alveolar samples. The best description of the desaturation of m-xylene from all subjects was obtained using three compartment pharmacokinetic models. Estimated from the residual variabilities of the desaturation curves, the precision of each sampling and analytical method was 0.13 for alveolar sampling, 0.14 for mainstream-mixed sampling, and 0.23 for sidestream mixed sampling. The breath concentration of m-xylene determined by sidestream mixed sampling averaged 83 percent of the concentrations determined by mainstream mixed sampling. In six subjects both mixed expired and alveolar breath samples were obtained. In these subjects the average m-xylene desaturation rates determined by both methods were comparable but substantially different from those determined by sidestream mixed sampling. The results indicated that for these subjects, sidestream sampling was not accurate while mainstream mixed sampling was accurate.
NIOSH-Author; Sampling-methods; Analytical-methods; Solvent-vapors; Organic-solvents; Sampling-equipment; Chromatographic-analysis; Air-sampling; Air-samplers; In-vivo-study
American Industrial Hygiene Association Journal