JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS the identity of which is unknown, the value of x E35.8 can be taken as 100 to determine the concentration of the chloroxylenol. This procedure will only introduce a serious error if the component happens to be 4-chloro- 2:5-dimethyl or 6-chloro-3:4-dimethylphenol. (Received: 29th June 7965) REFERENCES (1) Coggeshall, N. D. and Glesser, A. S. J. Am. Chem. Soc. 71 3150 (1949). (2) Clements, J. E. and Newburger, S. H. J. Assoc. O•c. Agr. Chemists 87 190 (1954). (3) Elvidge, D. A. and Peutrell, B. J. Pharm. Pharmacol. 18 Suppl. lilt (1961).

J. Soc. Cosmetic Chemists 17 9-16 (1966) ¸ 1966 Soc,ety of Cosmetic Chemists of Great Britain Application of Attenuated Total Reflectance IR spectroscopy to toilet articles and household products, 2.-Ouantitative analysis N. A. PUTTNAM, B. H. BAXTER, S. LEE and P. L. STOTT* Presented in part at the Xlth Colloquium Spectroscopicum Internationale, Belgrade 1963. Synopsis•The application of Attenuated Total Reflectance IR spectroscopy to the quantita- tive analysis of toilet articles and household products is described. The analyses were carried out by comparison with calibration curves prepared from standard samples. Examples are quoted of the determination of lauryl ether sulphate and salts of sulphated fatty alcohols in shampoos, the determination of glycerol in glycerine/sarcosinate solutions, the determina- tion of ethanol in aqueous ethanol systems, the simultaneous determination of pyrophosphate and alkyl aryl sulphonate in a household cleaner, and moisture in soap. The relative accuracy of these analyses was 4- 1.5 to -I- 3.0% and as each determination required less than 8 min they could be used for the routine control of such products. INTRODUCTION The application of Attenuated Total Reflectance IR spectroscopy to the qualitative identification of components in toilet articles and house- hold products has been described previously (1), together with the principle of the technique. From the quantitative aspect, although Beer's law is not valid for reflection spectra, it is still a fair approximation (2) and several reports have appeared of relationships having been established between formal "absorbance" and concentration. Fahrenfort (3) showed that such a relationship existed for the 907 and 992 cm -x absorptions of decene-1 in Nujol, while Wilhite and Ellis (4) described the determination of the *Research and Development Dept., Colgate-Palmolive Ltd., Manchester 5.