Derivatization procedure and HPLC determination of 2-ethoxyethanol in cosmetic samples

Ethylene glycol monoethyl ether or 2-ethoxyethanol finds a wide industrial application as a solvent for lacquers, inks, dyes, household products and as a surfactant. It is also found in cosmetics such as nail products, face cleansers, liquid soaps, oral care products, hair colours and fixatives. The potential hazard to human health of 2-ethoxyethanol following inhalation and dermal exposure has been recently reviewed and the European Cosmetic, Toiletry and Perfumery Association (COLIPA) has issued recommendations suggesting its non-use as a cosmetic ingredient. Therefore a simple and fast monitoring method is necessary for routine control to identify and quantify 2-ethoxyethanol in raw materials and finished cosmetics. We have developed a sensitive and selective method to determine 2-ethoxyethanol in complex matrices by precolumn derivatization with 1-naphthyl isocyanate and RP-HPLC analysis. Four laboratory-made cosmetic formulations (a nail lacquer remover, a baby oil, a skin lotion and an emollient O/W emulsion) containing three known amounts of 2-ethoxyethanol (0.1%, 2.0%, 5.0%) have been studied. The obtained results show that this chromatographic procedure provides a good estimate of the true concentration of 2-ethoxyethanol in complex matrices and it is reliable for routine analyses in quality control.