Gas-Liquid Chromatographic Determination of Methanol, Ethanol, and Isopropanol in Cosmetics, Using the Headspace Analytical Technique

Abstract

Abstract Methanol, ethanol, and isopropanol were determined in cosmetics by the gas chromatographic analysis of the vapors in the air space above a diluted sample. This method of headspace sampling compares favorably with other methods of determining alcohols, such as direct injection and isolation by codistillation. It is not necessary to isolate the alcohols before analysis because the method avoids the injection of nonvolatile substances in the sample, which may be detrimental to the column or the detector. The determination was carried out on a 6' × ¼" column packed with Chromosorb 101 coated with 1 % Ethomeen 18/60. An appropriate internal standard is used for the analysis of each alcohol to compensate for possible errors introduced by headspace sampling. The technique is applicable to various types of cosmetic products and is useful for the analysis of samples containing as little as 0.5% alcohol.