PENETRABILITY OF OILS IN HAIR 173 OOGONUT OIL_IaO•.TDG + Ioee 81pro 1045g•1 c• coconut oil mf , . 20O001 15 6 OOOONUT_OILi•.'!'D• + lans 811•m 1045961 c • coconut oii ref Coconut Oil 311 • [mtz] Figure 2. Spectra of positive ions of coconut oil deposited on a silicon wafer, including the highlighted characteristic positive ions of coconut oil. Characteristic positive ions of untreated hair: controls •br coconut-oil-treated hair. The TOF- SIMS spectra were obtained from the surface of the cross sections of untreated hair fibers. These spectra are very different from those obtained for the pure coconut oil. The spectra contain hydrocarbon and Na* peaks (Figure 4). The spectra do not contain any of the high-mass peaks observed in the coconut oil mass spectra. Characteristic positive ions of coconut-oil-treated hair. The positive TOF-SIMS spectra were obtained from the surface of the cross sections of hair fibers treated with coconut oil. As can be clearly seen, these spectra of the coconut-oil-treated fibers have intense peaks at 127, 183, 257, 383, 411,493, 467, and 495 m/z (Figure 5). These peaks match those of the coconut oil mass spectra, that is, these peaks are unique to the coconut oil. This comparison of the ion mass spectra suggests that coconut oil has indeed penetrated into

174 JOURNAL OF COSMETIC SCIENCE 1.2E+6 1.0E-6• ß . 4.0E+52 2.0E+5 0: H:•TANDAR•UT_OII._NEG.TDC - Io• 811•n 3752923 16 13 ' s I i I•ass [m/z] H:L•TANDAR!•ONUT OIL_NEQ.TDC. lens 811Jm 3752923 cts 7000i 4b 6'0 8•0 Mass [m/z] H:•I'ANDAR•ONUT_OIL NEG.TDC - Ions 81Wn 3752923 97 lOO 25000 I 20000 • Coconut Oil I ' "' ' '3l•0 .... 4(•)0 .... 5• .... 6l•0 .... 7l•)0' ' Mass [.Vz] Figure 3. Spectra of negative ions of coconut oil deposited on a silicon wafer, including the highlighted characteristic negative ions of coconut oil. the hair fiber interior. Mapping/imaging coconut oil in the fiber cross section via one of its unique ions (the positive ion at 127 (126.67) m/z) will confirm this conclusion. TOF-SIMS IMAGING OF COCONUT OIL IN HAIR The positive ion images at mass number 126.67 map the distribution of coconut oil in cross sections of an untreated control (Figure 6a) and coconut-oil-treated hair fibers (Figure 6b-d). The image of the untreated control hair fiber at mass number 126.67 in Figure 6a does not show much activity, suggesting essentially the absence of coconut oil. However, ion images at the same mass number of the coconut-oil-treated hair fibers clearly show partial (Figure 6d) to complete (Figure 6b,c) penetration of the coconut oil into the bulk of the hair fiber. Figure 6d shows only partial and unsymmetrical pen-