Investigation of charcoal cloth as a sorbent for integrated sampling of solvent vapors in mixed-expired breath using a new stainless steel sampler.

ABSTRACT

A stainless steel device for integrated sampling of solvents present in mixed-expired breath is described. During sampling, the subject inhales breathing air through commercial charcoal inhalation canisters. Exhaled breath is sampled from the mainstream using 45-mm wafers of charcoal cloth or from the sidestream on other sorbents. The device concentrates trace contaminants present in large volumes of breath. The charcoal cloth sorbent was evaluated for sampling and analysis of m-xylene and 1,1,1-trichloroethane under simulated physiological conditions. These samples were collected from atmospheres of either analyte generated at 35 degrees-40 degrees C and 80%-90% relative humidity to simulate an exhaled breath sample matrix. Concentrations sampled ranged from 2.2 to 190 mg/m3 for 1,1,1-trichloroethane and from 0.44 to 35.6 mg/m3 for m-xylene. Volumes sampled ranged from 10 to 50 L. The m-xylene samples were collected using a 3-wafer front and a 2-wafer backup bed of charcoal cloth; 1,1,1-trichloroethane samples were collected using a 10-wafer front and a 1-wafer backup bed. All samples were desorbed in carbon disulfide and analyzed via gas chromatography using a flame ionization detector. The volume of desorption solvent ranged from 1.7 to 2.5 mL per wafer of cloth. The quantitation limit is estimated to be 2.0 micrograms/L for 1,1,1-trichloroethane and 0.4 micrograms/L m-xylene for a 50-L sample. At least 80% recovery was obtained for m-xylene or 1,1,1-trichloroethane samples stored from 1 to 14 days after collection, if the samples were refrigerated at 0 degrees C after an initial 7-day storage period at room temperature. The recovery of hexane, 1-hexene, ethyl acetate, isopropanol, methylene chloride, and methyl isobutyl ketone from the charcoal cloth also has been investigated and is reported. With the exception of isopropanol, all analytes were recovered quantitatively from the charcoal cloth by desorption with carbon disulfide following storage for 1 to 17 days at ambient temperatures.