310 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS The chemical changes involved in the ammoniacal copper tartrate-Folin acid-molybdate are, at present, undefined. In all probability, the reduc- tion of the molybdenum is involved in the formation of the chromophore. In the preparation of the samples from typical cosmetic products, several factors that hindered the determination of allantoin were observed. In the case of some suppositories containing aluminum dihydroxyallantoinate, it was found that a precipitate sometimes formed in the cooled tiltrate. If this occurs, the precipitate should be removed by filtration. Certain lotions containing aluminum chlorhydroxyallantoinate or allantoin were found to be difficult to decolorize. In these cases, more activated carbon was added, and the solutions were refiltered. This process was continued until a clear colorless tiltrate was obtained. Some after-shave lotions were found to give a pink to red coloration when treated with hydrochloric acid prior to the addition of phenylhydrazine in the phenylhydrazine-ferri- cyanide method. If this occurs, the color is removed by adding activated carbon and filtering. The colorless tiltrate is boiled for 2-3 minutes, and the phenylhydrazine and potassium ferricyanide are then added as directed in the procedure, CONCLUSIONS The determination of allantoin and its aluminum derivatives in cosmetic preparations is easily carried out by the procedures outlined above. Inter- fering substances are removed by chloroform extraction, and the allantoin content of the sample is determined colorimetrically. (Received December 16, 1963) REFERENCES (1) S. B. Mecca, Proc. Sci. Sect. Toilet Goods ztssoc. No. 23, 8 (1955). Idern, Ibid. No. 39, 7 (1963). (2) Toilet Goods ztssoc. Spec. JVo. 72. (3) E. Young and C. Conway, y. Biol. Chern., 142, 839 (1942). (4) M. E1 Ridi, A. Magd, and M. E1 Marsy, Proc. Pharrn. Soc. Egypt, Sci. Ed., 36, 71 (1954). (5) A. Domnas, y. Biol. Chern. (Tokyo), 50, 46 (1961). (6) J. Deshusses and P. Desbaumes, Parrurns Cosrn•t. Sar'ons, 4, 192 (1961).

J. soc. cos. CHEM. 15, 311-326 (1964) COMPATIBILITY STUDIES OF ALUMINUM WITH PROPELLANT AND SOLVENTS FOR USE IN AEROSOLS By J. DE^N M:[NlVORD, PH.D.* Presented September 24-25, 1963, Seminar, Boston, Mass. ABSTRACT Exposure of aluminum alloy 1100-HI4 to fluorocarbons 11 or 12 or 95% ethyl alcohol for one year caused only very minor corrosion. A signif- icant increase in corrosion occurred when the alcohol was combtned with either fluorocarbon or a combination of both fluorocarbons. The addition of 5% water increased the corrosivity of the alcohol-fluoro- carbon mixture, whereas lar•er amounts of water appeared to have an initial retardin• effect. Inorllanic additives were found that effectively retarded the corrosion. Substitution of hi•her homolo•ue alcohols such as propyl, butyl, allyl, amyl and capryl formed noncorrosive solu- tions with fluorocarbon 11. INTRODUCTION The tremendous growth of the American aerosol industry in recent years has prompted a continuing search for new materials of construction for aerosol containers. The outstanding features of aluminum, such as light-weight, attractive design and ease of formability, have already gained public acceptance in the field of general packaging. Other out- standing advantages which aluminum can provide are directly related to its surface chemistry. It is both odorless and tasteless as well as hygienic, nontoxic and substantially sterile. Furthermore, its freedom from rust- ing, even under humid conditions, assures a continuing attractive ap- pearance and protects other contacting surfaces from rust staining. These same advantages could be of the same significant value in aerosol cans if aluminum was compatible with most aerosol formulations. Some corrosion was anticipated as a result of extensive studies in these laboratories on the compatibility of aluminum with various halogenated hydrocarbons. The possibility that some unusual aluminum reaction * Alcoa Research Laboratories, Chemical Metallurgy Div., New Kensington, Pa. 311