A procedure has been developed for measuring the steady state rate of permeation of commercial solvents through living human skin. To get the most consistent results, it was necessary with some solvents to normalize the solvent permeation rate of a given skin sample with its [3H]water permeation rate. For other solvents this was not necessary, so the un-normalized data were used. High [3H]water permeation rate also was used as a criterion for "defective" skin samples that gave erroneous permeability rates, especially for solvents having slow permeability. The linearity of the steady state data was characterized by calculation of the "percent error of the slope." The following permeability rates (g/m2h) of single solvents were measured: dimethyl sulfoxide (DMSO), 176; N-methyl-2-pyrrolidone, 171; dimethyl acetamide, 107; methyl ethyl ketone, 53; methylene chloride, 24; [3H]water, 14.8; ethanol, 11.3; butyl acetate, 1.6; gamma-butyrolactone, 1.1; toluene, 0.8; propylene carbonate, 0.7; and sulfolane, 0.2. The effect of [3H]water saturation on the shape of the presteady state portion of the permeation curve was determined and found to be very dependent on the solvent. The permeability of mixtures of DMSO and octyl acetate were measured. No octyl acetate was detected and the permeability of DMSO was proportional to its mole fraction in the mixture. The effect of two hours of solvent exposure on the viability of skin (based on DNA synthesis) was measured and found to be very dependent on the solvent.
473 Okamoto, G.; Mororumi, T. J . Electrochem. SOC. Jpn. 1953b, 21, 573. Okamoto, G.; Morozumi, T.; Sato, N.; Hachiya, M.; Nagayama, M. J . Electro-Okamoto, G.; Okura, T.; Sudo, N.Three-component solubility parameter envelopes have been useful in predicting the solubility/nonsolubility of polymers. The use of threecomponent solubility parameters in predicting both degree of solvency (as measured by inherent viscosity) and solubility/nonsolubility is demonstrated. Predictability is significantly worse if the total solubility parameter is substituted for the three-component parameters. Predictability is significantly improved if the effect of solvent molar volume on solubility is included. These conclusions are based on data for the solubility of three methacrylate polymers in 34 potential solvents, Inherent viscosity data for each of the polymers (for those solvents in which they are soluble) are also given. Three equations (two of which are based on available theory) are used to correlate inherent viscosity with solubility parameter.
cuts from distillations of several alkylbenzenes. Prolonged distillation at temperatures above 200°C. has been reported to cause significant decomposition of hydrocarbons (14)• The data given in Table I suggest that slight decomposition may occur even at temperatures well below 200°C.
DISCUSSIONThe results reported in Table I illustrate that components, once identified, can be determined if means are available for measuring their contributions to the sample spectrum free of sorption and vaporization effects. In most cases, this condition would require two separate instruments or two parallel inlet systems to one instrument, such that one sample admission is subject to sorption and selective vaporization while the other is free of them. The separations that occur on brass surfaces strongly suggest a crude gas-chromatography column (5, 11). This analogy, in turn, suggests that the versatility of the method might be much enhanced by provision for a choice of sorbing media, of eluents, and of operating temperatures.
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