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Predictable concentrations of vapours are generated by use of diffusion cells. After some modifications in the set-up first described 1956 by Fortuin (Anal. Chim. Acta 15:521), mixtures of different vapours can be produced reliably, i.e., independently of any manipulation at the outlet of the system, the rate and composition being constant over months and in good agreement with the pre-calculated data. The proper function is shown by means of vapour mixtures from benzene, toluene, n-octane, 2- and 3-xylene, generated by use of five diffusion cells, one for each component, coupled in series to the carrier gas line. Several further experiments are described to illustrate the flexibility and the limitations of the system.

An experiment procedure is described as a means for assessing the efficiency of skin-protecting measures against the vapors of hazardous substances. Bis(2-chloroethyl)sulfide (S-mustard) is used as the test substance. A continuous flow of S-mustard vapor is conducted through an exposure cell which is attached to the inner side of a rabbit's ear. From the difference in the concentrations measured before and behind the exposure cell, the absorption and the permeation rate of mustard into the skin is calculated. The skin damage, consisting of a reversible erythema, is quantified by measuring the optical transmittance of the exposed skin area during the following days and correlated with the respective absorption (dose) and exposure parameters (ct-product, with c=3-50 ng/cm3 and t=60 and 120 min). Reversible, i.e., completely healing, erythema are evoked by ct-products in the range of 250-2000 ng·min/cm3, corresponding to doses from about 0.1 to 1.1 µg/cm2. A comparison with older data reveals that human skin, in this respect, is about eight times more sensitive than the inner side of the rabbit's ear.