387 SKIN PERMEATION OF HAZARDOUS COMPOUNDS t R (min) m/z Potential analytes 4.78 2-[(methylsulfonyl)oxy]cyclohexyl methanesulfonate 1-bromo-3,4-dimethyl-2-pentene 5.15 41 (1-allylcyclopropyl)methanol 3,3-dimethyl-1,6-heptadiene 5-nitro-4-nonene 5.50 94, 110 2-isopropyl-furane 3-tert-butyl-1,5-cyclooctadiene 6.52 65,92 3-methylpyridine Aniline 6.84 94 2-dimethylaminopyridine 6.84 94 p-Cresol 7.28 95 Furfural 7.55 77, 112 Chlorobenzene 8.57 91, 106 Ethylbenzene 9.27 91, 106 m-/p-xylene 10.62 78, 104 Styrene 10.65 91, 106 o-xylene 12.55 120 o-/m-/p-ethyltoluene 1,2,3-trimethylbenzene 12.65 104 3-vinylpyridine 12.96 120 Isopropylbenzene 1,2,4-trimethylbenzene o-/m-/p-ethyltoluene 13.01 118 E-1-phenylpropene 2-propenyl-benzene 2,3-dihydro-1H-indene 13.40 91, 117 p-cymene 13.47 67, 93 dl-limonene 15.10 128, 129 Naphthalene 16.30 84, 133 Nicotine 17.00 152, 151 Acenaphthylene 17.55 41 Nonadecane 18.32 192 2-methylanthracene 19.60 192 1-methylphenanthrene 22.82 121 Squalene Table III. (Continued) of the identified peaks was compared with those of analytical standards prepared for this purpose. As it can be seen, the list includes isoprene, benzene- and aromatic-related com- pounds, pyridine, aniline, styrene, terpenes, nicotine, and polycyclic aromatic hydrocar- bons. From those compounds a selection of 15 compounds, including benzene, toluene, ethylbenzene, and xylenes (BTEX), chlorobenzene, styrene, p-cymene, limonene, naph- thalene, nicotine, acenaphthylene, 2-methylanthracene, and 1-methylphenanthrene, were selected as representative compounds for further studies. DESIGN AND EVALUATION OF THE SIMULATION CHAMBER CONDITIONS Once representative compounds from cigarette smoke have been selected, the homoge- neity of the simulation chamber atmosphere was assessed. In this sense, permeability experiments were carried out using Strat-M® membrane in the modified vertical diffusion

388 JOURNAL OF COSMETIC SCIENCE Franz cells placed at different locations inside the chamber (see Figure 2). An average concentration of 380 ± 40 ng cm−2 toluene was found in the synthetic membrane, deter- mined by TD-GC-MS while 13.9 ± 1.3 µg L−1 nicotine were found in the receptor solution, determined by LC-MS-MS. The obtained precision was appropriate, established as relative standard deviation (RSD) of five measurements (each corner and the center of the chamber), being lower than 10%. Thus, the placement of two electric fans inside the chamber assured a total homogenization of inner atmosphere, being adequate to perform dermal absorption studies in any position of the simulation chamber. DERMAL ABSORPTION IN FINITE DOSE CONDITIONS Finite dose experiment was carried out by the combustion of three cigarettes, which were consumed in approximately 10 min. Several parameters were monitored inside the expo- sure chamber to evaluate the combustion process during the experiment, giving the next values. Temperature and relative humidity were almost unaffected with average values of 24.8°C ± 0.2°C and 40.1% ± 0.9%, respectively. VOCs, CO, and CO 2 concentration background levels were 101, 0.45, and 1045 mg m−3, respectively, which increase to a maximum around 1200 s (20 min) of 8337, 130, and 3021 mg m−3, respectively, due to the cigarette combustion. With a similar profile, PM concentration background concentration was 0.01 mg m−3 that increased till 339 mg m−3. The concentration of target compounds in the chamber air was monitored by active sampling, at 5 min intervals, for a total time of 2 h. Figure 3 shows the concentration of nicotine, toluene, ethylbenzene, and p-cymene in the chamber air, selected as representative compounds. As it can be seen in Figure 3, the concentration profile shows a rapid increase of analyte concentration till a maximum at 15–20 minutes and later, a decrease in concentration at reduced speed. The reached maximum concentration values were 16.58, 3.15, 0.71, and 0.41 mg m−3 air for nico- tine, toluene, ethylbenzene, and p-cymene, respectively. The average concentration of these compounds in the 0–30-min interval were 9.70, 2.07, 0.26, and 0.41 mg m−3, respectively. 12 mL 0.9 % (w/v) NaCl adjusted to pH 7.4 Strat-M 0.7 cm2 0 4 8 12 16 20 A B C D E A B C D E 0 50 100 150 200 250 300 350 400 450 500 A B C D E Figure 2. Scheme of the modified vertical Franz diffusion cell and used in this study and results obtained from the five evaluated points inside the simulation chamber to evaluate air homogeneity. Nicog415ne ( L-1) Toluene(ng cm-2)