CHLORINATED BACTERIOSTATS 191 better performance than GCE. The voltammetric peak potentials of two chlorinated bacteriostats at the TFME were -1.84 V and -1.85 V and at the TFLE were -1.46 V and -1.55 V for TCC and triclosan, respectively thus, that electrode could not perform the simultaneous determination of TCC and triclosan in a mixture. Moreover, it is highly toxic to handle and may be lead to toxic materials in the products. A well-defined cathodic peak appeared at -1.46 V versus SCE for TCC, and the magnitude of the peak current appeared to be proportional to the concentration. Therefore, the TFLE and GCE were chosen for electroreduction and electroxidation in the determination of TCC and triclosan in cosmetic and pharmaceutical samples. Analytical results of HPLC and DPV are shown in Table III and show good agreement. CONCLUSION The electroreduction dechlorination of triclosan and TCC and electroxidation for the determination of triclosan were achieved in 0.1 M tetrabutylammonium hydroxide on lead-modified GCE and GCE, respectively. DPV is more sensitive and specific than HPLC for both qualitative and quantitative determination of TCC and triclosan. How- ever, the electroreduction process is suitable only for single quantitative determination of triclosan or TCC, because their peak potential is near, using the differential pulse mode. Electroxidation was suitable only for triclosan. The RI detector was suitable for single determination of both triclosan and TCC. The ability to extract TCC and triclosan from one sample preparation and resolve both analytes in 7 min using acetonitrile and water (70:30, v/v) by HPLC has been demonstrated. This LC-RI detection method was Table III Analytical Results for the Determination of Triclosan and TCC in Commercial Toothpastes, Deodorant Sticks, Anti-Acne Washing Cleansers, and Antibacterial Hand and Body Washes by High-Performance Liquid Chromatography (HPLC) and Differential Pulse Voltammetry (DPV) Toothpaste 1 Toothpaste 2 Deodorant 1 Deodorant 2 Deodorant 3 Deodorant 4 Samples Anti-acne washing cleanser 1 Anti-acne washing cleanser 2 Anti-acne washing cleanser 3 Antibacterial hand and body wash 1 Antibacterial hand and body wash 2 Antibacterial hand and body wash 3 Antibacterial hand and body wash 4 Antibacterial hand and body wash 5 a Number of determination (n = 3). 6 Relative standard deviation (RSD). c -, not indicated. Concentration (w/w % t Triclosan HPLC 0.273 (0.6%) 6 0.304 (2.9%) 0.177 (0.6%) 0.194 (0.8%) 0.684 (0.5%) 0.151 (2.2%) 0.277 (1.5%) 0.391(5.5%) 0.213 (2.0%) 0.237 (2.5%) 0.256 (2.6%) 0.195 (3.3%) 0.283 (0.2%) 0.281 (0.2%) DPV 0.305 (5.5%) 0.310 (5.5%) 0.183 (3.7%) 0.204 (5.8%) 0.676(2.1%) 0.155 (5.8%) 0.285 (4.0%) 0.408 (3.3%) 0.228 (2.4%) 0.212 (4.3%) 0.258 (2.2%) 0.206 (1.4%) 0.281 (5.6%) 0.285 (2.8%) TCC HPLC 0.225 (4.3%) 0.303 (1.8%) DPV 0.258 (4.4%) 0.306 (3.1 %)

192 JOURNAL OF COSMETIC SCIENCE found to be considerably faster than presently used methods for the determination of TCC and triclosan in cosmetic and pharmaceutical formulations. ACKNOWLEDGMENTS Financial support of this work by the Nation Science Council of the Republic of China is gratefully acknowledged (No. NSC 89-2113-041-007). REFERENCES (l) A. R. Cox,]. Soc. Cosmet. Chem., 38, 223 (1978). (2) R. J. Gilbert and P. E. U. Williams, Br.]. Clin. Pharm., 23, 579 (1987). (3) S. Jenkins, M. Addy, and R. Newcombe,]. Clin. Periodontal., 18, 140 (1991). (4) G. W. William and M. Addy,]. Periodontal., 63, 280 (1992). (5) M. Addy, S. Jenkins, and R. Newcombe,]. Clin. Periodontal., 17, 693 (1990). (6) S. Jenkins, M. Addy, and R. J. Newcombe,]. Clin. Periodontal., 20, 609 (1993). (7) J. S. Van der Hoeven, D. Cummins, N. J.M. Schaeken, and F. J. G. Van Ouderaa, Caries Res., 27, 298 (1993). (8) M. B. Pinkey and N. C. Corbin, J. Soc. Cosmet. Chem., 35, 351 (1984). (9) F. Yackovich, N. K. Poulsen, and J.E. Heinze,]. Soc. Cosmet. Chem., 37, 99 (1986). (10) F. Yackovich, C. A. Wagner, and J.E. Heinze, J. Soc. Cosmet. Chem., 40, 265 (1989). (11) K. W. Kwochka and J. J. Kowalski, Am. J. Vet. Res., 52, 115 (1991). (12) K. A. Rustom, M. Carpentier, M. De La Brassine, and Ch. M. Lapiere,J. Appl. Cosmet., 4, 111 (1991). (13) A. Kanetoshi, H. Ogawa, E. Katsura, T. Okui, and H. Kaneshima, Arch. Environ. Contam. Toxicol., 17, 637 (1988). (14) A. Kanetoshi, E. Katsura, H. Ogawa, T. Ohyama, and H. Kanesshima, Arch. Environ. Contam. Toxicol., 23, 91 (1992). (15) K. Kawahima, S. Nakaura, M. Yamaguchi, S. Tanaka, and A. Takanada, Eisei Shikunsho Hokoku, 105, 28 (1987). (16) M. Bruze, S. Fregert, and B. L. Junggren, Photodermatology, 2, 32 (1985). (17) L. D. Gruenke and J.C. Craig,]. Anal. Toxicol., 11, 75 (1987). (18) M. C. Bare, F. Tekaia, and P. Bourlioux, Appl. Environ. Microbial., 55, 1911 (1989). (19) United States FDA, Fed Reg., 22, 33644 (1991). (20) A.H. A. Heyn, M. F. Zaranyika, and J.M. Goldberg, Intern. J. Environ. Anal. Chem., 11, 131 (1982). (21) M. Brikel, W. Erking, and N. Wetzelsberger, Meth. Find. Exp. Clin. Pharmacol., 15, 623 (1993). (22) M. Graovac, M. Todorovic, M. I. Trtanj, M. M. Kopecni, and J. J. Comar, J. Chromatogr., 705, 313 (1995). (23) R. G. Achari and D. V. Chin,]. Soc. Cosmet. Chem., 32, 163 (1981). (24) R. J. Gilbert, S. B. Fraster, and F. J. G. Van der Quderaa, Caries Res., 21, 29 (1987). (25) J. H. Lesser, R. Z. Shustina, and D. V. Ovadia,j. Chromatogr., 410, 95 (1987). (26) S. Sano, Y. Maeda, K. 0. M. Yamamoto, and T. Masui, Shizuoka-ken Eisei Kankyo Senta Hokoku, 32, 41 (1989). (27) M. P. Demkowicz, V. Chauhan, D. A. Stern, and F. G. Vasquez,]. Chromatogr., 671, 351 (1994). (28) R. M. Pemberton and J.P. Hart, Anal. Chim. Acta., 390, 107 (1999). (29) A.]. Bard and A. Merz,]. Amer. Chem. Soc., 101, 2959 (1979). (30) P. Zumun and C. L. Perrin, Organic Polargraphy (John Wiley & Sons, New York, 1969), p. 256. (31) M. M. Baizer, Organic Electrochemistry: An Introduction and a Guide (Marcel Dekker, New York, 1973), p. 280.