EFFECTS OF HUMECTANTS ON EMULSION OCCLUSIVITY 269 (17) T. Ito and K. Okamoto, Effect of cosmetic cream and raw material on insensible water vapor loss through the human skin, in Preprint of ScientijS'c Papers, the 6th Congress of the International Fed- eration of Societies of Cosmetic Chemists, Barcelona, Sept. 20-25, 1970, Vol. 11, pp 601-609. (18) O.K. Jacobi, Nature of cosmetic films on the skin. J. Soc. Cosmet. Chem., 18, 149-160 (1967). (19) I. Lo, A. T. Florence, J.P. Treguier, M. Selllet, and F. Puisieux, The influence of surfactant HLB and the nature of the oil phase on the phase diagrams of nonionic surfactants-oil-water systems, J. Coif. Interface. Sci., 59, 319-327 (1977). (20) M. Buzier and J. C. Ravey, Solubilization properties of non-ionic surfactants. I. Evolution of the ternary phase diagrams with temperature, salinity, HLB and A.C.N., J. Coll. Interface Sci., 91, 20- 33 (1983).

j. Soc. Cosmet. Chem., 36, 271-286 (July/August 1985) Evaluation of relative shampoo detergency D. THOMPSON, C. LEMASTER, R. ALLEN, and J. WHITTAM, Forrest C. Shaklee Research Center, 1992 Alpine Way, Hayward, CA 94545. Received October 31, 1984. Presented at the Annual Meeting of the Society of Cosmetic Chemists, New York, December 6-7, 1984. Synopsis An analytical protocol is described for the assessment of relative shampoo detergency on hair by which raw materials, prototype formulations, and competitive products can be objectively contrasted. Hair tresses are soiled with a standard nine-component synthetic sebum mixture using 2% and 10% sebum in hexane solutions. Soil removal is determined under three test conditions: bulk bath washer, traditional "finger squeeze," and controlled-pressure apparatus. Gas chromatography of the residual sebum components serves as the analytical basis for the investigations. Comparisons are based upon the "tracking" of 20 gas chro- matograph peaks which are indicative of the various sebum fractions. An internal control sample is used to compensate for any sample-to-sample variation in soiling level. Solutions (10%) of different surfactant types, ammonium lauryl sulfate (ALS), sodium laureth 2-sulfate (AES) and sodium alpha olefin C14-C16 sulphonate (AOS), are evaluated with both single and multiple soiling and washing cycles to investigate sebum partitioning as a function of the active ingredient type. Sebum fraction removal is seen to be dependent upon: 1. Washing technique--The finger squeeze method of sample treatment is the least reproducible of the sample treatments investigated due to the high degree of operator interaction required. 2. Surfactant system--The type of surfactant determines which sebum fractions are removed and to what extent. 3. Multiple cycles--Repeated washing and soiling cycles indicate that ALS leaves the least amount of residue with repeated use. INTRODUCTION The theory of detergency dates back over halfa century (1-4). In essence, the theoretical principles and tenets of surface chemistry can be used to describe the removal of soil from a solid surface based upon molecular interactions at the solid-liquid and liquid- liquid interfaces (5-7). Experimental detergency evaluation of various surfactant so- lutions, on the other hand, has been more difficult. Part of this difficulty lies in agreement on a standard soil, a controlled substrate, a consistent and reproducible soiling process, a standard soil removal procedure and, finally, analytical methodology capable of measuring subtle changes in minor components from the soiled substrate. Significant process has been made over the years in arriving at a standardized procedure 271