HAIR ANALYSIS BY ToF-SIMS Table I Positive-ion ToF-SIMS Spectral Assignments· of Cationic Conditioners Ion assignment EB (C1sH31)2-N-(CH3)2 EB (C,sH37)2-N- (CH3)2 I C,6H33 EB C11H3s-N-(CH3)2 I C,6H33 EB (C16H33)2-N-(CH3)2 EB C,6H33-N-(CH3)z C,sH31 EB C,6H33-N-(CH3)2 I C14H29 EB C,sH31-N-(CH3)2 I C14H29 EB (C14H29)2-N- (CH3)2 EB C,4H29-N-(CH3)2 I C13H21 EB C14H29-N-(CH3)2 I C12H2s EB C 13 H27-N-(CH3)2 I C12H2s EB (C12H2s)2-N-(CH3)2 m/z 522+ sos + 494 + 424+ 410+ 396+ 269

270 JOURNAL OF COSMETIC SCIENCE Table II Negative-ion ToF-SIMS Spectral Assignments of the Surface Lipids of Hair Negative ions (A) C20H41Cos­ C20H41C00- C19H39Cos­ C,9H 3 9Coo­ Cl8H37Cos­ C17H35Cos­ C 17 H35COO C17H33Cos­ C17H33Coo­ C16H33COS C16H33COO­ C15H31COS­ C,5H31Coo- SIMS peak (m/z) 341 325 327 311 313 299 283 297* 281 285 269 271 255 900+--_._ _ __._ ________________ �--- 700 600 .1!1 500 C u 400 3GO 200 100 □ □ □ 220 240 260 260 300 320 340 360 380 400 m/z Figure 3. Negative-ion ToF-SIMS spectrum of sodium dodecyl sulphate (SDS) film D, Alkyl sulphates. (m/z = 265 -), probably due to the higher substantivity of the longer alkyl chain components at the hair surface. Another common cleaning reagent incorporated in shampoo formulations for hair is sodium laureth sulphate (SLES). Therefore, its interaction with the hair surface during wet chemical treatment is potentially important. Examination of the negative-ion ToF­ SIMS spectrum of SLES indicates an impure mixture, with the major spectral species being, surprisingly, sodium dodecyl sulphate (m/z = 265-) (Figure 5). Nevertheless, the expected range of ethoxylated C 12, C14, and C16 alkyl chain derivatives was also appar-