HPLC-TEA ANALYSIS OF NDELA 221 As illustrated in Figure 2, the correlation (r) of the regression line for the TEA is much better with the internal chromatographic standard than using the peak heights alone (r = 0.9996 versus r = 0.986). A comparison of the coefficients of variation for the peak height versus the peak height ratio in Table IV indicates that the ICS improves the analytical precision by about 4%. The drop from _ 8% to ñ 4% is substantial. ACKNOWLEDGEMENTS This work was supported by the Cosmetic, Toiletry, and Fragrance Association, Inc. We wish to thank Norman Estrin, Mel Goodman, Gary Henderson, Lester Isbrandt, Aaron Cooper, John McNally, Ira Rosenberg, C. T. Desmond, Bernard L. Kabocoff, M. Graber, Jack Winstead, and other members of the CTFA Nitrosamine Task Force for their advice and guidance. REFERENCES (1) R. Montesano and H. Bartsch, Mutagenic and carcinogenic N-nitroso compounds: Possible environ- mental hazards, Mutat. Res,, 32, 179-228 (1976). (2) L. Griciute, "Carcinogenicity of N-nitroso Compounds and Their Possible Role in the Development of Human Cancer," in Environmental Carcinogens, Selected Methods of Analysis, H. Egan, Ed., IARC Scientific Publication No. 18 (International Agency for Research on Cancer, Lyon, France, 1978), Vol. l, pp 3-9. (3) D. Schm•hl, Problems of dose-response studies in chemical carcinogenesis with special reference to N-nitroso compounds, CRC Critical Rev. Toxicol., 6, 257-281 (1979). (4) L. R. Ember, Nitrosamines: Assessing the relative risk, Chem. Eng. News, 20-26 (March 3 l, 1980). (5) W. Lijinsky and S.S. Epstein, Nitrosamines as environmental carcinogens, Nature, 225, (5227), 21-23 (1970). (6) E. A, Walker, P. Bogovski, and L. Griciute, Eds., Environmental N-Nitroso Compounds Analysis and Formation, IARC Scientific Publication No. 14 (International Agency for Research on Cancer, Lyon, France, 1976). (7) P. N. Magee, R. Montesano, and R. Preussman, "N-Nitroso Compounds and Related Carcinogens," in Chemical Carcinogens, C. E. Searle, Ed., ACS Monograph 173 (American Chemical Society, Wash- ington, D.C., 1976), pp 491-625, (8) P. Bogovski and E. A. Walker, Eds., N-Nitroso Compounds in the Environment, IARC Scientific Pub- lication No. 9 (International Agency for Research on Cancer, Lyon, France, 1975). (9) IARC Monographs on the Evaluation of the Carcinogenic Risk of Chemicals to Humans: Some N-Nitroso Compounds (International Agency for Research on Cancer, Lyon, France, 1978), Vol. 17. (10) E. A. Walker, L. Griciute, M. Castegnaro, and R. E. Lyle, Eds., Environmental Aspects of N-Nitroso Compounds, IARC Scientific Publication No. 19 (International Agency for Research on Cancer, Lyon, France, 1978). (1 l) T. Y. Fan, J. Morrison, D. P. Rounbehler, R. Ross, and D. H. Finer N-nitroso-diethanolamine in synthetic cutting fluids: A part-per-hundred impurity, Science, 196, 70-71 (1977). (12) I. Schmeltz, S. Abidi, and D. Hoffman, Tumorigenic agents in unburned processed tobacco: N- nitrosodiethanolamine and 1,1-dimethylhydrazine, Cancer Lett., 2, 125-132 (1977). (13) T. Y. Fan, U. Goff, L. Song, D. H. Fine, G. P. Arsenault, and K. Bieman, N-nitrosodiethano- lamine in cosmetics, lotions, and shampoos, Food Cosmet. Toxicol., 15, 423-430 (1977). (14) W. Lijinsky, M.D. Reuber, and W. B. Manning• Potent carcinogenicity of nitrosodiethanolamine in rats, Nature, 288, 589-590 (1980). (15) I. Rosenberg, The CTFA program on nitrosamines: An overview, CTFA Cosmet. J., 30-37 (July/ August/September 1981). (16) H. Ohshima, M. Matsui, and T. Kawabata, Gas chromatographic separation of hydroxylated N- nitrosamines,•J, Chromatogr., 169, 279-286 (1979). (17) I. E. Rosenberg, J. Gross, T. Spears, and U. Caterbone, Methodology development for the deter*

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