176 JOURNAL OF COSMETIC SCIENCE 8UNSVROI1 + Ions 851Jm 325115 cts 55 • [n•z] 100 120 8UHSVROI1 + ions 851Jm 325115 cts 147 140 160 1•) Mms [•z] 8UNSVROI1 + Io•s 85Fn 325115 cts Coconut Oil 311 521 Mass [•z] Figure 5. Spectra of positive ions from the surface of a cross section of coconut-oil-treated hair fibers. Clearly, a high count of (highlighted) positive ions characteristic of coconut oil was established within the interior of coconut-oil-treated hair fibers. II. Penetration of Mineral Oil ION MASS SPECTRA Characteristic positive ions of pure mineral oil The characteristic positive TOF-SIMS spectra are dominated by hydrocarbons that are not unique for mineral oil. However, a series of peaks with 14Da intervals were observed in the high-mass range of 300-400 m/z. These peaks can be used to map the mineral oil within the hair fiber, since these peaks are not found in the positive spectra of untreated hair. The positive ion at 361 (361.26) m/z will be used for imaging of mineral oil in the hair fiber (Figure 7a).

PENETRABILITY OF OILS IN HAIR 177 [Add] [[Add]:427.580] - 126.67 Scale: 10pro (Io9) Untreated: Coconut oil distribution [Add] [[Add]:427.580] - 126.67 Cts: 85833 Max: 28 Scale: 10prn Coconut oil distribution [Add] [[Add]:427.580_'l- 126.67 Ct$: 132750 Max: 56 Scale: 10pro (log) Coconut oil distribution [Add] [[Add]:427.580] - 126.67 Cts: 229094 Max: 60 Scale: 10pm coconut oil distribution Figure 6. Imaging the presence of coconut oil at mass number ! 26.67 m/z (one of the characteristic positive ions of coconut oil) in the surface of (a) untreated and (b-d) coconut-oil-treated cross-sectioned hair fibers. Characteristic negative ions of pure mineral oil. The negative spectra also contain a series of peaks with a 14Da interval in the mass range above 100 m/z. A representative negative ion mass spectrum of mineral oil is shown in Figure 7b. Mass spectra of characteristic positive ions of untreated hair: controls for coconut-oil-treated hair. The TOF-SIMS spectra were obtained from the surface of the cross sections of untreated hair fibers and showed no peaks corresponding to the mineral oil. The spectra were dominated by hydrocarbon and sodium peaks and showed contamination from coconut oil and polydimethysiloxane (Figure 8). The spectra do not contain any of the high-mass peaks observed in the coconut oil mass spectra.