PENETRABILITY OF OILS IN HAIR 175 10000- 2UNSVROiI + lofts 1251J'n 496920 cts 15 0 , 2UNSVROI1 + Ions 1251Jm 496920 cts lOOO c lOO 12o Mass !mtz] ß 109 1 •7 137 ' 140 Mass Ira/z] 2UNSVROI1 + Ions 12r"4m 4Eft& cts Siloxane I 326 413 465 529 •[•1 Figure 4. Spectra of positive ions found on the surface of cross sections of an untreated hair fiber (se•ing as control). No characteristic positive ions of coconut oil were detected within the interior of untreated hair. etration of the oil. The oil has penetrated into the fiber center from one side, but is restricted to the periphery on the other side. Ion images of cross sections in Figures 6b,c show complete penetration of the coconut oil, even though penetration is non-uniform. There is more oil in the periphery than in the fiber center. The intensity of color reflects relative amounts, but does not give exact amounts. The exact quantification requires calibration with known quantities of oil in the hair. Even then it may not be exact, because penetration of the beam over the sample surface may be non-uniform. Therefore, this method can give information only on penetration and relative distribution patterns of materials, but not on the exact amounts present in a given fiber. The same format was used to investigate penetration of mineral oil into the hair shaft.

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).