Design and evaluation of an exhaled breath sampler for biological monitoring of organic solvents.

We designed a breath sampler based on a tube which collects the final portion of exhaled air. The passage of successive fractions through a layer of activated charcoal is controlled by a three-way valve. This system was validated in a controlled atmosphere of n-hexane and toluene at four concentrations between 12 and 110 mg m-3 and 12 and 115 mg m-3, respectively. Uptake volumes of 0.1, 0.2 and 0.31 were tested at relative humidities of 46% and 98%. There were no significant differences in the recoveries obtained under any of the conditions tested. We confirmed the reproducibility between successive samples in volunteers and exposed workers, and found no significant differences between the different sampling conditions studied. Our system enriches the sample in an adsorbent cartridge by collecting successive fractions of end-exhaled breath from one or more exhalations until the amount required by the analytical method has been accumulated. It is portable, economical and highly operative in the field.