Method for determining hydrogen peroxide in emulsions 619

620 K. C. James and E. Tsirivas It thus appears that the analytical procedure described can be used for the analysis of hydrogen peroxide emulsions, subject to prior standardisation of the method to the paxticular formula. Preparations containing cationics should be treated with caution however. The potential of ethyl acetate as extracting solvent was also investigated. It could be used satisfactorily in the determination of hydrogen peroxide in aqueous solutions, but the results were sensitive to the presence of every surface active agent examined. REFERENCES 1 Kingzett, C. T. Report on the atmospheric oxidation of phosphorus, and some reactions of ozone and hydric peroxide. J. Chem. Soc. 792 (1880). 2 Henderson, G. and Newton, J. M. The solubilization of iodine by a non-ionic surfactant. Pharm. Acta. Helv. 41 228 (1966). 3 Henderson, G. and Newton, J. M. The antibacterial activity of iodine in aqueous solutions of a non-ionic surfactant. Pharm Acta. Helv. 44 129 (1969). 4 Hickman, J. B. Determination of hydrogen peroxide in the presence of organic matter. Proc. W. Va. Academy Sci. 23 76 (1951). 5 Dukes, E. K. and Hyder, M. L. Determination of peroxide by automatic colorimetry. Anal. Chem. 36 1698 (1964). 6 Ovenston, T. C. J. and Rees, W. T. The spectrophotometric determination of small amounts of hydrogen peroxide in aqueous solution. Analyst 75 204 (1950). 7 Azaz, E., Donbrow, M. and Hamburger, R. Assay of micro-scale amounts of hydroperoxide in aqueous non-ionic surfactant solutions by a spectrophotometric method. ibid. 98 663 (1973). 8 Evans, D. F. Blue perchromic acid. J. Chem. Soc. 4013 (1957). 9 Glasner, A. and Steinberg, M. Photometric determination of chromium as perchromic acid in ethyl acetate solution. Anal. Chem. 27 2008 (1955). 10 Sastri, M. N. and Sundar, D. S. Quantitative extraction of chromium as blue perchromic acid with tri-n-butyl phosphate. Z. Anal. Chem. 195 343 (1963). 11 Tuck, D. G. A solvent extraction method for the determination of microgram amounts of chromium. Anal. Chim. Acta 27 296 (1962). 12 Haggett, M. L., Jones, P. and Wynne-Jones, W. F. K. Peroxycomplexes as intermediates in the catalytic decomposition of hydrogen peroxide. Diss. Faraday Soc. 29 153 (1960). 13 Cosmetic and pharmaceutical formulary. Croda. P. 6. 14 Suggested formulae for the manufacture of pharmaceutical and cosmetic preparations based on Dehydag products. Henkel & Cie, Dusseldorf. p. 153.