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Aug. 13, 2009

Determination of 1,4-Dioxane in Cosmetics

Authored by Dr. Kim W. Baughman, Director of Development, Microbac Laboratories, Inc.

Recent studies have been released concerning the presence of trace levels of 1,4-dioxane in various cosmetics products, including: shampoos, bubble baths, lotions and creams. This compound has long been an environmental concern and there is increasing interest in measuring the levels in consumer products.

The FDA has been evaluating the potential risk of 1,4-dioxane in cosmetics products since the 1970s and, over this period, levels have actually decreased. The FDA has not considered it to be a major health hazard, primarily because the levels are relatively low and because 1,4-dioxane is only in contact with the skin for short periods because of its rapid evaporation rate. Regardless, heightened consumer awareness has brought this issue to the attention of manufacturers and the response has been to increase the testing and reporting of levels in various products.

Dioxane is not actually added to these products. It is a by-product of the manufacturing process. A process called ethoxylation is used to polymerize some of the detergents and emulsifiers used in manufacturing. 1,4-Dioxane can be formed during this step. The FDA has provided guidance to manufacturers advising them how to minimize the formation using a process called vacuum stripping at the end of the polymerization step.

Dioxane has traditionally been determined in water and soil using a purge and trap gas chromatography / mass spectroscopy (GC/MS) method. The purge and trap sample concentration is not as amenable to cosmetics samples, therefore, most analyses are performed using some form of heated headspace sample introduction into the GC/MS. Detection limits of 1 g/g (full scanning mass spectroscopy) can be achieved using this method.

Scientists at Microbac Laboratories, Inc. have developed a single headspace method for use with a broad range of product types: lotions, creams, shampoos and bubble baths. The method has proven to be versatile and provides accurate results. For more information about our testing and research capabilities, please contact Microbac Laboratories.

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