6 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS obtain mass spectra of the volatile compounds. The spectra were first interpreted and then matched with the NBS library of reference spectra. In this way, it was possible to propose structures for a number of components which were then confirmed using au- thentic standards. Confirmation was made by dynamic headspace gas chromatography with a flame ionization detector using two columns of different polarity (OV 170 ! and FFAP) and completed by static headspace GC/MS, again with the two different columns. Several series of homologous compounds were identified, including alkanes, alkenes, alcohols, aldehydes, ketones, acids, and •/-lactones. The complete list of identified components is given in Table I. A partial chromatogram obtained by GC/MS is shown in Figure 3. It ranges from about scan N ø 400 to scan N ø 1200, with a complete run requiring 1500 scans to register. The sequences of homologous compounds can be clearly seen either on the total ion current chromatogram or, even better, on the selected mass chromatogram. Thus, the chromatogram of the fragment ion at m/e = 56 is very characteristic of alkenes, al- cohols, aldehydes, and lactones, while the fragment ion at m/e = 58 selectively indi- cates ketones. In a similar manner, acids can be characterized by the fragment ion at m/e = 60. On this chromatographic system acids were very poorly eluted due to the inadequate polarity of the stationary phase (OV 1701). Proper elution and resolution of these compounds was achieved, however, on the FFAP column. The alkanes were not unambiguously identified using the OV 1701 column since they co-eluted either with alkenes (for the first terms of the series) or with aldehydes (for the last members of the series). Proper resolution and positive identifications were achieved, however, on the FFAP stationary phase. Some peaks present in the chromatogram of Figure 3 were identified as artifacts (si- Table I List of All Volatile Compounds Detected and Identified From Human Hair and Scalp Alkanes Alkenes Alcohols Aldehydes Tridecane 1-octene 1-pentanol Pentanal Tetradecane 1-nonene 1-hexanol Hexanal Pentadecane 1-decene 1-heptanol Heptanal Hexadecane 1-undecene 1-octanol Octanal Heptadecane 1-dodecene 1-nonanol Nonanal Octadecane 1-tridecene 1-decanol Decanal 1-tetradecene 1-undecanol Undecanal Dodecanal Tridecanal Ketones Acids •/-Lactones 2-pentanone Acetic acid •/-butyrolactone 2-hexanone Propionic acid •/-valerolactone 2-heptanone Butyric acid •/-caprolactone 2-octanone Valeric acid •/-heptalactone 2-nonanone Caproic acid •/-octalactone 2-decanone Heptanoic acid •/-nonalactone 2-undecanone 2-dodecanone 2-tridecanone

VOLATILE COMPOUNDS FROM HAIR AND SCALP 7 b 23 8 1/. 1 2 7 o 2021 I I i I I I ,. 5 m/e= 56 10 17 9 11 13n•• 1416 L 19 20,•_• I I I I I I mle:58 21 mle = 60 6 12 18 _ I I I I l 500 700 900 11 • 0 Sc(]n Number Figure 3. Partial chromatograms of the volatile compounds from human hair and scalp obtained using the static headspace sampling procedure with an OV 1701 capillary column on a GC/MS instrument. The upper trace is the total ion current chromatogram while the others are specific mass chromatograms (m/e = 56, 58, and 60 respectively). The peaks marked "a" are siloxane artifacts arising from septum bleed. 1: Butyric acid 2: 1-hexanol 3: 2-heptanone 4: Heptanal 5: 1-decene 6: Valetic acid 7: 1-heptanol 8: 2-octanone 9: Octanal 10: 1-undecene 11: •/-butyrolactone 12: Caproic acid 13: •/-valerolactone 14: 1-octanol 15: 2-nonanone 16: Nonanal 17: 1-dodecene 18: Heptanoic acid 19: •/-caprolactone 20: 1-nonanol 21: 2-decanone 22: Decanal 23: 1-tridecene b: 6-methyl-2-heptanone. loxanes) arising from septum bleed. These compounds were not observed during the GC/FID runs since septumless instruments were used in this case. INTERSUBJECT VARIATIONS The chromatographic profiles of the volatile compounds present on the scalp and the hair were recorded over an experimental population of 20 subjects. Basically, the same species as listed in Table I were always encountered. However, wide intersubject dis- crepancies could be observed. For some subjects, the acids or the alkanes, although present, were barely detectable. Likewise, the balance between the alkenes, the alde- hydes, and the ketones showed very wide intersubject variations. Differences in the amounts of the volatile compounds present on the scalp and the hair were also observed. The chromatograms of Figures 4 and 5 were obtained by the dy- namic method employing 130 mg of hair. In the first case (Figure 4), the subject was a