2 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS achieved using headspace techniques which are of particular interest when volatile con- stituents are to be detected and identified in a non-volatile or less-volatile matrix. For static sampling, the sample is enclosed in a closed system at a constant temperature (4). The volatile compounds present in the matrix undergo a partition between the condensed phase and the gaseous phase ("headspace") and can be detected by injecting an aliquot of the latter. If the equilibrium between the two phases is reached (thus the term "static headspace"), the composition of the vapor phase is representative of the initial composition of the sample. For dynamic headspace sampling, the volatile compounds of interest are continuously stripped from their matrix by a purge gas (4) and subsequently trapped on an adequate adsorbant. After completion of the stripping procedure, the adsorbant is heated and the evolved volatile species are directed toward the chromatographic column. In this study, both the static and the dynamic methods of headspace sampling were adapted for the analysis of the volatile compounds from SSL. EXPERIMENTAL EXPERIMENTAL POPULATION The samples were obtained from an experimental population of 20 adults (male and female) aged 25-45 and one child (male) aged three years. All of these subjects had hair of mid-length and natural (non-colored and non-permanent waved). The sampling pro- cedure was performed four days after the last washing with a shampoo. STATIC HEADSPACE PROCEDURE The skin surface lipids were collected from the scalp and hair using a piece of surgical cotton (about 200 mg) held with a pair of tweezers. The cotton was passed on the scalp and hair of the subject by taking one lock of hair at a time and scrubbing it from root to tip with the cotton. This procedure collected about 3 mg of material for each half of the scalp, with the volatile portion constituting, of course, only a fraction of that amount. The piece of cotton was then enclosed in a 6-ml septum capped vial which was inserted into a commercial headspace sampler (HS6 Headspace Sampler © from Perkin Elmer, Norwalk, CT). The sample was conditioned at 120øC for two hours before injecting. DYNAMIC HEADSPACE PROCEDURE A commercially available instrument was used (Girdel DCI System © from Delsi, Su- resne, France) (5,6). About 100 mg of hair were cut from the subject's head and en- closed in the sample oven of the instrument. The latter was maintained at 50øC and purged by a flow of nitrogen (20 ml ß min-•). The volatile compounds which evolved from the hair were swept up by the purge gas and directed toward an adsorbant trap packed with Tenax and maintained at -50øC. The purge and trap procedure was carried out for 35 minutes. The trap was then back flushed by the carrier gas of the chromatograph and quickly heated to 240øC (the heating rate was about 2000øC ß min-•, which means that the plateau value was reached within 6-8 seconds).

VOLATILE COMPOUNDS FROM HAIR AND SCALP 3 CONDITIONS FOR GC: FIRST SYSTEM A borosilicate glass capillary (length = 40 m internal diameter = 0.25 mm) was preconditioned using the BaCO 3 procedure of Grob (7-9). The tube was then dynami- cally wall-coated with FFAP stationary phase. The operating conditions were the fol- lowing: Injector temperature: 250øC (for static headspace only no injector is used on the dy- namic headspace instrument) Flame ionization detector temperature: 230øC Column temperatures: initial temperature: 30øC for 1 minute programmed to 70øC at 25øC ß min- 1 isothermal at 70øC for 6 minutes programmed from 70øC to 215øC at 4øC ß min- 1 final hold at 215øC for 5 minutes Carrier gas: helium, inlet pressure 0.9 bar Splitless injection according to Grob (10,11) CONDITIONS FOR GC: SECOND SYSTEM A borosilicate glass capillary (length = 30 m internal diameter = 0.25 mm) was preconditioned using the persilylation procedure of Grob (12). The tube was then dy- namically coated with OV 1701 stationary phase. The operating conditions were the following: Injector temperature: 250øC (for static headspace only no injector is used on the dy- namic headspace instrument) Flame ionization detector temperature: 230øC Column temperatures: initial temperature: 30øC for 1 minute programmed to 80øC at 25øC ß min- • isothermal at 80øC for 6 minutes programmed from 80øC to 210øC at 5øC ß min- • final hold at 210øC for 5 minutes Carrier gas: helium, inlet pressure 0.7 bar Splitless injection according to Grob (10,11) CONDITIONS FOR GC/MS For the GC/MS experiments, the static headspace procedure was used in conjunction with the two chromatographic systems (FFAP and OV 1701). The commercial instru- ment (Finnigan 4000 GC/MS system, from Finnigan MAT, San Jose, CA) was operated under electron impact conditions at 70 eV. CONDITIONS FOR GC/MS: SYSTEM FOR CHIRAL RECOGNITION A borosilicate glass capillary (length = 17 m internal diameter = 0.25 mm) was preconditioned according to the persilylation procedure of Grob (13, 14). The tube was then statically wall-coated from a dichloromethane solution containing OV 1701 sta- tionary phase (5 mg/ml) and Nickel (II)-bis (3-heptafluorobutyryl-(1R)-camphorate) (0.3 mg/ml). The latter compound was synthetized according to Schurig (15-17). Due to the presence of this chiral complex dissolved in the stationary phase, the column was