238 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS The present data clearly indicate that the currently used spectrophotometric assay er- roneously estimates the purity of CCC as a result of metal-free chlorophyll derivatives having even higher extinction coefficients than their coppered counterparts and/or car- otenoids. In order to control the quality of CCC, the Cu/N index should be employed in conjunction with the absolute percentage of copper and nitrogen content. These values have to be in range of those calculated for a 100% pure CCC. Interference by carotenoids can be avoided by obtaining the total absorptivity of the red peak for the preparation, rather than spectrophotometric measurements in the blue region of the spectrum, as presently employed. REFERENCES (1) A.M. Humphrey, Chlorophyll, Food Chem., 5, 57 (1980). (2) S. A. Chernomorsky and A. B. Segelman, Biological activities of chlorophyll derivatives, NJ Med., 85, 669 (1988). (3) M. E. Wall, Preparation of chlorophyl derivatives for industrial and pharmaceutical use, US Agri- cultural and Chemistry Bureau, 299, 1 (1951). (4) J. C. Kephart, Chlorophyll derivatives: Their chemistry, commercial preparation and uses, Economic Botany, 9, 3 (1955). (5). New and Nonofficial Remedies (J. B. Lippincott Co., Philadelphia, 1953), pp. 57-58. (6) H. W. Voigtlander and H. M. Henning, Das Desodorans "Chlorophyllin," Arzneim. Forsch., 3, 182 (1953). (7) F. D. Pickel, J. J. Scalan, and R. Heggie, Water-soluble copper derivatives of chlorophyll, Drug Stand., 22, 173 (1954). (8) M. Strell, A. Kalojanoff, and F. Zuther, Zur Analytik von Chlorophyll--Praparaten des Handels, Arzneim. Forsch., 6, 8 (1956). (9) M. Sato, I. Fujimoto, T. Sakai, T. Aimoto, R. Kimura, and T. Murata, Effect of sodium copper chlorophyllin on lipid peroxidation. IX. On the antioxidative components in commercial preparations of sodium copper chlorophyllin, Chem. Pharm. Bull., 34, 2428 (1986). (10) S. H. Schanderl, G. L. Marsh, and C. O. Chichester, Color reversion in processed vegetables. II. Model system studies, J. Food Sci., 30, 317 (1965). (11) R. F. Boyer, Modern Experimental Biochemistry (Benjamin/Cummings Publishing Company, Redwood City, California, 1993), p. 383.