48 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS REFERENCES (1) Laycock, H. H. and Mulley, B. A. Determination of the homologue composition of some alkyl trimethyl quaternary ammonium antibacterial agents by gas chromatography. J. Pharm. Pharmacol. 18 (Suppl.) 9s (1966). (2) Cannizaro, R. D. and Lewis, D. A. Gas chromatographic analysis of aerosols by pressur- ised liquid sampling. J. Soc. Cosmet. Chem. 20 353 (1969). (3) Curie point pyrolyser 'Column'. Pye-Unicam Chromatography Bulletin 2. 8 (1968). BIBLIOGRAPHY Suggested further reading and references Ion exchange chromatography. Helfferich, F. Ion exchange (1962) (McGraw-Hill, New York). Gas chromatography. Kaiser, R. Gas phase chromatography (1963) (Butterworths, London). Thin layer chromatography. Stahl, E. (Ed.) Thin layer chromatography (1969) (Allen & Unwin Ltd, London). Liquid chromatography. Kirkland, J. J. Modern practice of liquid chromatography (1971)(Wiley- Interscience, New York). Gel permeation chromatography. Altgelt, K. H. and Segal, L. (Eds) Gel permeation chromato- graphy (1971) (Marcel Dekker, New York). Pyrolysis and reaction gas chromatography. Ettre, L. S. and McFadden, W. H. (Eds) Ancillary techniques of gas chromatography (1969) (Wiley-Interscience, New York). uv/visible spectrophotometry } Infra-red spectrophotometry Williams, D. H. and Fleming, I. Spectroscopic methods in organic chemistry (1966) (McGraw- Nuclear magnetic resonance spectroscopy Hill, New York). Mass spectrometry Fluorescence spectrophotometry. Parker, C. A. Photoluminescence of solutions (1968) (Elsevier, Amsterdam). Atomic absorption spectrophotometry. Slavin, W. Atomic absorption spectrophotometry (1968) (Interscience, New York). Polarography. Milner, G. W. C. The principles and applications of polarography and other electroanalyticalprocesses (1962) (Longmarts, London). X-ray microanalysis. Heinrich, K. F. Electron probe microanalysis--a review. Appl. Spectrosc. 22 (5) (1968). Specific ion electrodes. Simon, W., Wuhrmann, H-R., Vagttk, M., Pioda, L. A. R., Dohner, R., and gtefanac, Z. Ion selective sensors. Angew. Chem. lnt. Ed. Engl. 9 445 (1970). Auto-analysis. Advances in automated analysis (1969) (Mediad, New York). Surfactants. Hummel, D. Identification and analysis of surface active agents by infra-red and chemical methods. 2 vols (1962) (Interscience, New York). Rosen, M. J. and Goldsmith, H. A. Systematicanalysisofsurface active agents 2nd edn (1972) (Wiley-Interscience, New York). Polymers. Stevens, M.P. Characterisation and analysis of polymers by gas chromatography (1969) (Marcel Dekker, New York). Hummel, D. Infra-red analysis of polymers, resins and additives--an atlas. 2 vols (1969) (Wiley-Interscience, New York). Slade, P. E. Jr, and Jenkins, L. T. (Eds) Techniques and methods of polymer evaluation. Vol. 1. Thermal Analysis (Marcel Dekker, New York) (1966). General. Newburger, S. H..4 manual of cosmetic analysis (1962) (Association of Official Analy- tical Chemists Inc., Washington D.C.). Meites, L. (Ed.) Handbook of analytical chemistry (1963) (McGraw-Hill, New York).

J. Soc. Cosmet. Chem. 25 49-58 (1974) ¸ 1974 Society of Cosmetic Chemists of Great Britain The application of microcalorimetry to research in the field of toilet preparations G. P. ADAMS* Presented at the 7th Congress of the International Federation of Societies of Cosmetic Chemists, in Hamburg, Germany, 19th September 1972 Synopsis---A differential MICROCALORiMETER has been adapted for ADSORPTION studies on biological substrates. The instrument provides reproducible quantitative information on the HEAT change associated with the interaction of the material of interest with the substrate. When this heat change is combined with information on the amount of material adsorbed obtained using conventional analytical techniques, an indication of the adsorbate-adsorbent interaction is obtained. The CALORiMETER is also capable of giving information on the rate of adsorption, the time required to reach thermal equilibrium and whether or not appreciable adsorption occurs in times encountered during product application. Subsidiary experiments indicate whether the adsorbed material is likely to withstand rinsing or whether the adsorption characteristics are grossly affected by the presence of detergent. The paper describes the apparatus and techniques employed and gives general examples of the applications of the method to illustrate its utility. INTRODUCTION One of the objectives of a toilet preparations formulator may be to develop a product which deposits a functional ingredient onto a particular surface. This surface could be hair, skin or dental enamel. A feature common to all surface processes is the driving force required to achieve a more stable state by a reduction in the free energy, and it is responsible for the phenome- non known as adsorption. Unilever Research, Isleworth Laboratory, Middlesex. 49