Factors influencing migration of NIAS: Model experiments with 7,9-di-tert-butyl-1-oxaspiro(4,5)deca-6,9-diene-2,8-dione (Arvin 8)

The transfer of intentionally added substances (IAS) and non-intentionally added substances (NIAS) from food contact materials is usually investigated by means of migration tests. However, detailed knowledge about the stability of NIAS in food simulants during migration is scarcely available although it is considered essential for risk assessments. In this study we performed migration and stability tests with the known NIAS breakdown product 7,9-di-tert-butyl-1-oxaspiro(4,5)deca-6,9-diene-2,8-dione (S.1, a.k.a. Arvin 8) in 4 % acetic acid and 50 % ethanol. Maximum migration values for S.1 were reached faster in 50 % ethanol but decreased significantly over time due to the instability of S.1 in this solvent. LC-MS/MS and LC-QTOF-MS analysis enabled the determination of two transformation products including the known 3-(3,5-di-tert-butyl-1-hydroxy-4-oxo-2,5-cyclo-hexadien-1-yl)propionic acid (S.2), whilst the second (S.3) was not described, yet. The preparative isolation of S.3 by countercurrent chromatography (CCC) followed by ¹H NMR analysis enabled to identify the second compound as ethyl 3-(3,5-di-tert-butyl-1-hydroxy-4-oxocyclohexa-2,5-dien-1-yl)propanoate. The short-term formation of the novel intermediate product S.3 was the main reason for the high instability of S.1 in 50 % ethanol. In contrast to that, the polymer matrix was shown to be responsible for the slowdown of the lactone-ring opening reaction converting S.1 into S.2 and S.3. The present findings confirmed the potential influence of different food simulants and co-migrating polymer matrix residuals on the migration test results of S.1. Knowledge on these effects is a key factor for the meaningful food safety risk assessment of the migration of S.1.