METHOD FOR HAIR DAMAGE 295 samples can also provide meaningful data. This procedure may, therefore, be used for qualitative screening of a large number of dansylated hair samples in a relatively short period of time without the use of expensive instrumentation. CONCLUSIONS We have demonstrated that hair treated with dansyl chloride shows strong fluorescence under ultraviolet light. The fluorescence intensity is a function of the amount of dansyl chloride binding to certain specific groups, such as N-terminal amino acids, thiols, and phenolic hydroxyls, in the hair and can be measured in a spectrofluorometer at very low levels. Our studies have shown that any damage to hair leading to destruction or gener- ation of DANS-C1 reactive groups will correspondingly decrease or increase the fluores- cence emission of dansylated hair. Using this procedure, we were able to demonstrate hair damage due to various causes, namely, weathering, ultraviolet radiation, and chemical bleaching. The following observations support these conclusions: ß Weathered hair samples, namely tip ends, do not fluoresce as strongly as the rela- tively unweathered root ends, suggesting destruction of certain amino acids due to weathering. Furthermore, a progressive decline in the fluorescence emission from root to tip was observed over the entire length of a 61-cm-long hair sample treated with dansyl chloride. ß Exposing hair to ultraviolet radiation prior to the dansyl chloride reaction decreases the fluorescence emission, presumably due to the destruction of UV-sensitive amino acids such as tyrosine, histidine cysteine, and lysine. ß Increase in DANS-Cl-induced fluorescence of chemically bleached hair indicates bleach- and/or alkalinity-mediated protein hydrolysis generating additional dansyl chloride reactive groups. ß Furthermore, studies indicate that sensory evaluation of fluorescence emission of dansylated hair can also provide reliable data. Thus, the sensory method may serve to short-cut the spectrofluorometric procedure for quick, qualitative screening of dan- sylated hair samples. Thus, dansyl chloride can be a useful tool to study certain types of hair damage. The procedure is simple, sensitive, and reliable, and damage can be assessed both visually and instrumentally. REFERENCES (1) R. Beyak, F. Meyer, and G. Kass, Elasticity and tensile properties of human hair. I. Single fiber test method. J. Soc. Cosmet, Chem,, 20, 615-626 (1969). (2) J. C. Garson, The transverse vibrational properties of keratin fibers in the presence of water and other materials, Int. J. Cosmet, Sci., 2, 231-241 (1980). (3) J. A. Swift and A. C. Brown, The critical detemination of fine changes in the surface architecture of human hair due to cosmetic treatments, J, Soc. Cosmet, Chem., 23, 695-702 (1972). (4) R. Beyak, G. S. Kass, and C. F. Meyer, Elasticity and tensile properties of human hair. II. Light radiation effects, J. Soc. Cosmet. Chem., 22, 667-678 (1971). (5) E. Tolgyesi, Weathering of hair, Cosmet. Toilet. 98, 29-33 (1983).

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