Determination of Diethylene Glycol in Toothpaste

A rapid and simple method using gas chromatography (GC) for the determination of diethylene glycol (DEG) in toothpaste was developed. DEG in toothpaste was extracted with methanol containing 1, 4-butanediol as the internal standard by using an ultrasonic bath. The centrifuged and filtrated methanol extracts were analyzed by GC on an InertCap 624 capillary column. The recoveries of DEG from toothpaste fortified at the levels of 0.1, 0.5 and 1.0%, were 103.6, 99.9, 99.4%, respectively. The quantitation limit of DEG in toothpaste was 0.05%. The proposed method could be applied to other cosmetics on the market without any interference. By using this method, DEG was detected the presence in 2 out of 10 toothpaste samples set to the hotel. This analytical method should be useful for quality control for manufacturers and importers of cosmetics.