692 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISES k-igure 5. Simultaneous gas-liquid chromatography of dichlorophcne and hexachloropheue In another study (Fig. 6), a comparison was made of the GLC of un- silylated dichlorophene in chloroform, after silylation by the method given above and by the injection of 10 t•l of the silylating agent 0.5 minute after injecting the chloroformic solution of dichlorophene. In each case the retention times were the same. As anticipated, in absence of silylating agent, severe tailing was obtained. It is interesting to note that silylation may also be performed on the column. If quantitative, this procedure may be useful in assay by direct injection followed by column silylation. (Received January 22, 1970)

DETERMINATION OF HEXACHLOROPHENE 693 Figure 6. Effects of silylation on the gas-liquid chromatography of dichlorophene REFERENCES (1) Methods of Analysis Subcommittee of Society of Cosmetic Chemists of Great Britain, Estimation of hexachlorophene in cosmetic products, J. Soc. Cosmet. Chem., 19, 213 (1968). (2) Elvidge, D. A., and Peutrell, B., The determination of hcxachlorophene and other phenols in pharmaceutical preparations by a AE spectrophotometric method, J. Pharm. Pharmacol., 13, Suppl. lilt (1961). (3) Porcaro, P. J., and Shubiak, P., Detection of subnanogram quantities of hexachloro- phene by electron capture gas chromatography, Anal. Chem., 40, 1232 (1968). (4) Porcaro, P. J., Detection of dichlorophene, hexachlorophene, and other related bis- phenols by gas-liqnid chromatography, Ibid., 36, 1664 (1964). (5) Wisniewski, J. V., How to determine hexachlorophene in soap. Facts Methods, 8, 10 (1967). (6) Wehrli, A., and Kovats, E., Gas chromatographische Charakterisierung organischer Ver- bindungen, Teil III, Berechnung der Retentionindices aliphatischer, alicyclischer und aromatischer Verbindungen, Helv. Chim. Acta, 42, 2709 (1959). (7) Kovats, E., ZusammenhSnge zwichen Structur und gas chromatographischer Daten organischer Verbindungen, Z. Anal. Chem., 181, 359 (1961) .