DETERMINATION OF 1,4-DIOXANE 337 CONCLUSION The method presented here has been shown to be a relatively simple, sensitive, and precise method for the determination of 1,4-dioxane in ethoxylated products. By suitable minor modifications in sample treatment or chromatographic conditions to accommodate specific interferences which may occur, it can be adapted to a wide range of such products. REFERENCES (1) J. A. Wenninger, Speech before the Cosmetic Session, Annual Educational Conference, F.D.A., Dec. 12, 1979. (2) Submission for the Record, Hearing before the Subcommittee, Oversight and Investigations Committee on Interstate and Foreign Commerce (House of Representatives)July 19, 1979. (3) M. F. Argus,J. C. Arcos, and C. Hogh-Ligeti, J. Natl. Cancer Inst. 35,949-958 (1965). (4) C. Hogh-Legeti, M. F. Argus, andJ. C. Arcos, Br.J. Cancer 24, 164-167 (1970). (5) R.J. Kociba, S. B. McCollister, C. Park, T. R. Torkelson, and p.J. Gehring, Toxicol. Appl. PharmacoL 30, 275-286 (1974). (6) T.J. Birkel, C. R. Warner, and T. Fazio,J. Assoc. Off. Anal. Chem. 62,931-936 (1979). (7) W. H. Braun,J. Chromatogr. 133,263-266 (1977). (8) H.J. Weiser (Proctor & Gamble), at the CTFA Dioxane Task Force Meeting, Arlington, VA.,Jan. 17, 1980. (9) E. W. Ciurczak, Use of Pre-Columns in the Gas Chromatographic Analysis of Surfactant Mixtures, Varian GC Application Note #36, January 4, 1980.

j. Soc. Cosmet. Chem., 31,339-359 (December 1980) Profilometry of skin--A useful tool for the substantiation of cosmetic efficacy THOMAS H. COOK, Elizabeth Arden Research Center, Lilly Research Laboratories, 307 East McCarty Street, Indianapolis, Indiana, 46285. Received May 23, 1980. Presented at the SCC Scientific Seminar, San Francisco, May 15-16, 1980 Synopsis Profilometry is a method of evaluating surface texture utilizing a stylus instrument. This method has been adopted by several skin researchers. Replicas of the horny layer have been used to transfer the peak and valley geometry from the skin's surface to a material more suited for stylus measurements. The surface profiles generated by the profilometers are quantified with a number of roughness parameters. Various methods of analysis have been used to investigate changes in the skin's topography as a function of: 1) direction of scan, 2) extensibility of the skin, 3) existing tension in the skin, 4) cohesographic force, 5) body site, 6) subject's age and 7) treatment with skin care products. The replication methods STYLUS INSTRUMENTS ROUGHNESS PARAMETERS and ANALYSIS METHODS used by the various investigators applying profilometry to the skin are reviewed. The results of quantitative assessments of the EFFECTS OF COSMETIC PRODUCTS on the skin's topography are also reviewed. I. INTRODUCTION The characterization of the effects of skin care cosmetic products on the topography of the horny layer may become a valuable component in the substantiation of treatment products' efficacy. A first step toward characterization is developing a method to measure and quantify the geometric properties of the skin's surface. Quantitatively evaluating the geometric properties of surfaces is not unique to cosmetic claim substantiation. Industrial engineers have been measuring surface texture of machine parts since World War I!. The method, employed by these engineers, commonly called profilometry uses a stylus instrument to generate profiles of the surface under study. The method has been developed to the point where standardized profile parameters exist to quantify surface texture (roughness, waviness and lay). In addition to profilometry, other less established methods have been used to measure surface texture, for example: capacitance methods (1), laser roughness meters (2) and other optical methods (3). 339