Contact Allergens from Surfactants. Atmospheric Oxidation of Polyoxyethylene Alcohols, Formation of Ethoxylated Aldehydes, and Their Allergenic Activity

□ Ethoxylated surfactants are susceptible to oxidation upon air exposure. We have previously studied the rate of peroxidation and formaldehyde formation in the chemically well-defined ethoxylated alcohol C12H25(OCH2CH2)5OH. Formaldehyde is a common cause of contact allergy. The aim of the present study was to identify other oxidation products that could be formed upon air exposure of the ethoxylated alcohol and to determine their allergenic activity. It was shown that air oxidation of C12H25(OCH2CH2)5OH gave all the theoretically possible aldehydes of the general formula C12H25(OCH2-CH2)nOCH2CHO (n=0–4) and that the major oxidation product was C12H25(OCH2CH2)4OCH2CHO, dodecyltetraoxyethyleneoxyacetaldehyde. The structure elucidation and synthesis of these aldehydes are here presented for the first time. The major aldehyde was shown to be a contact allergen with the same sensitizing capacity as that of formaldehyde. A dose–response relationship was observed in the sensitization studies. The allergens were formed from the surfactant itself and the skin reactions cannot be explained due to any impurities that may be present in a technical quality of the surfactant. Cases of allergic contact dermatits to ethoxylated surfactants have been reported. To avoid the formation of allergenic oxidation products it is important to control the conditions for storage, handling, and transportation of ethoxylated surfactants.