title: N-nitroso-N-methyldodecylamine and N-nitroso-N-methyltetradecylamine in hair-care products.
abstract: N-Nitroso-N-methyldodecylamine and N-nitroso-N-methyltetradecylamine, which cause urinary bladder tumours in experimental animals, were detected in several hair-care products formulated with N,N-dimethyldodecylamine oxide. Quantitative determinations were made using a gas-liquid chromatograph interfaced with a thermal energy analyser and using [1-14C]N-nitroso-N-methyldodecylamine as an internal standard. The presence of the two nitrosamines was confirmed by high-pressure liquid chromatography with a thermal energy analyser as detector, by photolysis of samples and by combined gas chromatography-mass spectometry. To test the reproducibility of the method, a single shampoo was selected for replicate analysis and was found to contain 90 +/- 8 ppb N-nitroso-N-methyldodecylamine and 37 +/- 11 ppb N-nitroso-N-methyltetradecylamine. Levels of N-nitroso-N-methyldodecylamine in other hair-care products ranged from 11 to 873 ppb and those of n-nitroso-N-methyltetradecylamine from 8 to 254 ppb.
mesh_terms: D002273:Carcinogens / Q000032:analysis*; D006203:Hair Preparations / Q000032:analysis*; D009602:Nitrosamines / Q000032:analysis*
chemical_list: D002273:Carcinogens; D006203:Hair Preparations; D009602:Nitrosamines; C009914:N-nitrosomethyldodecylamine; C029648:N-nitrosomethyltetradecylamine