Stability of the secondary antioxidant bis(2,4-di-tert-butylphenyl)pentaerythritol diphosphite in food simulants

To establish the stability of Ultranox 626 (an antioxidant added to plastics) in food simulants under migration conditions, migrations tests have been performed. A method has been developed for the determination of Ultranox 626 in the aqueous food simulants distilled water, 3% (w/v) acetic acid, and 15% (v/v) ethanol and in the fatty food simulants 95% (v/v) ethanol and isooctane. The method uses reversed-phase high-performance liquid chromatography with ultraviolet detection at 230 nm, is fast, and can be run automatically. To determine the stability of Ultranox 626,it was heated in each of the listed food simulants under the conditions stipulated in EU regulations for testing for compliance with migration limits. These experiments showed that this additive had acceptable stability in water, 15% and 95% (v/v) ethanol, and isooctane but that it decomposed completely in 3% (w/v) acetic acid. Migration testing with 3% acetic acid is of no use, since by the end of the testing regime the additive will have undergone substantial or total decomposition, and the level detected will not reflect the true level of migration. The EU Commission should replace 3% acetic acid with 15% ethanol as an appropriate test simulant for the determination of Ultranox 626 in all types of acid-and alcohol-containing foodstuffs. A number of experiments were carried out to develop a suitable method for the determination of Ultranox in fat simulants such as olive oil and HB 307. It appeared not possible, within the scope of this project, to obtain a method suitable to establish the stability of Ultranox 626 in fat simulants. Best results were obtained by freezing out the fat at -80 degrees C, but recovery was limited to 50%, which was insufficient for the intended purpose. Further experiments are required to establish the stability of Ultranox 626 in fat simulants such as olive oil and HB 307.