PENETRABILITY OF OILS IN HAIR 179 1.5E+6- • 1.0E+6- 5.0E+5 oe 0 BN1.TDC- ions 811Jm 3466808 cts '"'" • lO 15 Uass [m/z] 25 30000: BN1.TDC- Ions 811•n 3466808 cts 25000• • Uass [.Vz] BNI.TDC - Ions 811Jm 3466808 cts 103 , 149 179 ] 116 129 ' 143 193 •[• , • 317 7b. Spectra o• characteristic .•adv• ions o• m•n•ra[ o•] &posk• on a s•]•con w•r. dots, but there is not much activity, suggesting it is quantitatively close to zero. The evidence is quite conclusive that mineral oil does not penetrate hair. This is not quite unexpected, since mineral oil is nonpolar and the cortex of hair is polar and, therefore, has no affinity for mineral oil. COMPARISONS BETWEEN COCONUT AND MINERAL OIL PENETRATION Ion spectra and images clearly identified coconut oil within the hair fiber cross section. The diffusion of coconut oil ranges in depth from partial to complete penetration of the

180 JOURNAL OF COSMETIC SCIENCE UNTREATEDP2.TDG + Ions 1211zn 11320•g c•ts untmated UNTREATEDP2.TDC + Ions 1211•n 1132059 cts untreated 2500• o lOO 140 160 uass [m/z] UNTREATEDP2,TDC * Ions 121vm 1132059 cls unimated 221 229 • 265 279 •ass [m/z] UNTREATEDP2.TDC + lens 1211]m 1132059 •s untreated • [ • Cocooil [2E] PUS 300 400 500 600 Mass InVzl Figure $. Typical spectra of positive ions oerom the surface of a cross section of an untreated hair fiber. No characteristic positive ions o• mineral oil were de[ec[ed within contamination f•om coconu• oil •nd polydime•hylsilox•ne entire hair fiber cross section, even though penetration is non-uniform. There is more oil in the periphery than in the fiber center. This is clearly demonstrated in the images obtained by mapping positive ions of mass number 126.67 m/z. It is important to point out that the intensity of color in these images reflects relative amounts of the materials mapped but does not give exact amounts. However, valid and reliable comparisons of the relative distribution patterns can be made. Mineral oil, on the other hand, was not detected within the hair fiber cross section. This is clearly shown in the positive ion images carried out at mass number 361.26 m/z, which is unique to mineral oil. Both the images of untreated and mineral oil-treated hair