DETERMINATION OF DIOXANE LEVELS 183 Table IV Concentration Levels of Dioxane in 20 Commercial Cosmetic Products in the US Market Cosmetic name Concentration of dioxane found (ppm) Lotions i 0.54 2 n.m.* 3 0.69 4 1.38 Range: n.m.-1.38 Creams Shampoos Conditioners Cleansers 2 1.01 3 n.m. 4 n.m. Range: n.m.- 1.01 1 1.72 2 4.12 3 1.16 4 1.88 Range: 1.16-4.12 1 1.13 2 n.m. 3 n.m. 4 O.6O Range: n.m.-1.13 2 1.74 3 2.26 4 O.73 Range: n.m.-2.26 * n.m., Not measurable, or concentration is less than 0.1 ppm. CONCLUSION A quick method (taking about six minutes to perform), with higher sensitivity (0.1 ppm), accuracy, and reproducibility (better than 5% in intra- and inter-assay) for determination of dioxane in cosmetic products was developed. The recovery of dioxane- by solid-phase extraction in cosmetics can be over 80%. ACKNOWLEDGMENTS We very much thank Professor Martin Pope of New York University and Dr. T. D. Lee of Clinical Research Associates for reading our paper. REFERENCES (1) M. F. Argus. J. Nat. Cancer Inst., 35, 949 (1965). (2) R. J. Kociba, Toxicol. Appl. Pharmacol., 30, 275 (1974). (3) G. Barker, in Surfactants in Cosmetics, M. M. Rierger, Ed. (Marcel Dekker, New York, 1985), p. 18.

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