that faster dye formation chemistry causes more dye to form outside versus inside hair, and this color is subsequently washed off during the rinsing step. The same effect was seen when prewashing hair in tap water containing copper with a shampoo product containing either no histidine or 0.1% histidine. Addition of low levels of a copper- specifi c chelant such as histidine in a shampoo prevents copper accumulation in hair as shown in the ICP-OES data and leads to improved color uptake and color over multiple wash cycles. ACKNOWLEDGMENTS: The authors would like to thank the Procter & Gamble Company for support of this work. REFERENCES (1) J. M. Marsh, “Hair coloring,”in Practical Modern Hair Science: Allured Business Media, Carol Stream, IL, T. Evans and R. R. Wickett. Eds. (2012), pp. 117–156 . (2) J. F. Corbett, Benzoquinone imines. Part 1. p-Phenylenediamine-Ferricyanide and p-amino phenol- Ferricyanide redox systems, J Chem Soc (B)., 3, 207–212 (1969). (3) J. F. Corbett, Benzoquinone imines. Part II. Hydrolysis of p-benzoquinone monoimine and p-benzoquinone di-imine, J Chem Soc (B), 3, 213–216 (1969). (4) S. Godfrey, W. Staite, Bowtell P., and J. Marsh, Metals in female scalp hair globally and its impact on perceived hair health, Int. J. Cosmet. Sci., 35(3), 264–271 (2013). (5) J. M. Marsh, M. G. Davis, R. L. Lucas, R. Reilman, P. B. Styczynski, Li C., M. Mamak, D. W. McComb, R. E. A. Williams, S. Godfrey, K. R. Navqi, and V. Chechikand, Preserving fi bre health: reducing oxida- tive stress throughout the life of the hair fi bre, Int. J. Cosmet. Sci., 37(S2), 16–24 (2015). (6) J. M. Marsh, M. G. Davis, M. J. Flagler, Y. Sun, T. Chaudhary, M. Mamak, D. W. McComb, R. E. A. Williams, K. D. Greis, L. Rubio, and L. Coderchand, Advanced hair damage model from ultra-violet radiation in the presence of copper, Int. J. Cosmet. Sci., 37(5), 532–541 (2015). (7) B. Sarkar and Y. Wigfi eld, The structure of copper (II)-histidine chelate, J. Biol. Chem., 242(23), 5572– 5577 (1967). Table III dE Values for Initial Color versus Wash Cycles (Std Error in Parenthesis) Shampoo details Shade dE color change between initial color and Wash cycles 2 5 8 12 0% histidine 77/44 7.59 (0.2) 7.73 (0.3) 6.99 (0.2) 6.70 (0.2) 0.1% histidine 77/44 4.93 (0.3) 5.32 (0.3) 5.71 (0.3) 5.60 (0.3) 0% histidine 4/6 3.42 (0.2) 4.57 (0.2) 5.43 (0.2) 6.12 (0.2) 0.1% histidine 4/6 2.58 (0.3) 3.65 (0.3) 4.68 (0.2) 5.68 (0.2) JOURNAL OF COSMETIC SCIENCE 278