JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS Committees for 1970-71 EDUCATION COMMITTEE Mr. D. F. Williams (Chairman) Mr. K. V. Curry Mr. W. W. F. Scotland PUBLICATIONS COMMITTEE Mr. A. Herzka (Chairman) Mr. J. M. Blakeway Mrs. H. Butler Mrs. A.M. Parks Mr. G. A. C. Pitt GENERAL PURPOSES COMMITTEE Mr. C. Pugh (Chairman) Mr. K. M. Godfrey Mr. J. S. Cannell Mr. T. A. Brock Mrs. H. Butler PUBLICITY AND RECRUITMENT COMMITTEE Miss C. M. Stewart (Chairman) Mr. P. C. Adams Mr. M. Callingham Mr. D. E. Davies Mr. A. Herzka Mr. J. C. McCarthy MEMBERSHIP COMMITTEE Mr. T. A. Brock (Chairman) Mr. P. C. Adams Mr. R. Somerville PROGRAMME COMMITTEE Mr. P. C. Adams (Chairman) Mrs. H. Butler Mr. A. Herzka Mr. J. C. McCarthy SCIENTIFIC COMMITTEE Dr. C. H. Johns (Chairsnan) Mr. T. A. Brock Dr. E. Cronin Mr. R. E. Davies Dr. A. W. Middleton Dr. M. N. Naylor SOCIAL COMMITTEE Mr. J. C. McCarthy (Chairman) Mr. W. W. F. Scotland Miss A. E. Young

J. Soc. Cosmet. Chern. 22 3-14 (1071) ¸ 1971 Society of Cosmetic Chemists of Great Britain The analysis of odoriferous vapours, including head space analysis B. DUDLEY SULLY* Presented at the Symposium on "Perfumery", organised by the British Society of Perfumers and the Society of Cosmetic Chemists of Great Britain, at Eastbourne, Sussex, on 21st April 1970. Synopsis--HEAD SPACE ANALYSIS is normally concerned with the analysis of VAPOURS, but the 'perfumer would prefer to know the composition of a liquid that •vill reproduce a given vapour composition. The problem is illustrated by glc experiments with DIBUTYL PHTHALATE containing LINALOL and IONONE (1:4 by volume) which produces a vapour containing linalol and ionone in a weight ratio of more than 15: 1. It is shown that the vapour can be brought into equilibrium with a suspended micro-drop of dibutyl phthalate to reproduce the original liquid composition. EXPERIMENTS show that the slow step in the attainment of EQUILIBRIU• is the diffusion of the odoriferous yapours through the air space and that the rate is much increased by working under a partial vacuum. The procedure is illustrated by the equilibration of a micro-drop of dibutyl phthalate with the odoriferous yapours from a living ROSE. A similar experiment was made with culinary grade THYME. A complete analysis of an odoriferous vapour such as that produced by coffee, strawberries, or flowers such as roses would involve the identifica- tion and quantitative determination of hundreds and perhaps thousands of different organic compounds. The ultimate aim of the chemist is to reproduce an odour by chemical and physical techniques of analysis and without the use of the sense of smell, but at the present time this is extreme- ly laborious if not quite impossible. The identification and determination of perhaps 99•/o or more of the constituents of an odour is possible with the latest techniques, but this is far from sufficient and many have found that a synthetic mixture prepared according to an almost complete analysis of an essential oil may be no more than reminiscent of the original odour. *Bush Boake Allen Ltd., London, E.15.