Determination of the overall migration from silicone baking moulds into simulants and food using ~1H-NMR techniques

摘要

Different silicone baking moulds (37 samples) were characterized with respect to potential migrating substances using ~1H-NMR, RP-HPLC-UV/ELSD and GC techniques. In all cases cyclic organosiloxane oligomers with the formula [Si(CH_3)_2-O]_n were identified (n = 6 ... 50). Additionally, linear, partly hydroxyl-terminated organosi-loxanes HO-[Si(CH_3)_2-O]_n-H (n = 7 ... 20) were found in 13 samples. No substances other than siloxanes could be detected, meaning the migrants mainly consist of organopolysiloxanes. Based on this knowledge, a ~1H-NMR quantification method for siloxanes was established for the analysis of both simulants and foodstuffs. Validation of the ~1H-NMR method gave suitable performance characteristics: limit of detection 8.7 mg kg~(-1) oil, coefficient of variation 7.8% (at a level of 1.0mgkg~(-1) food). Migration studies were carried out with simulants (olive oil, isooctane, ethanol (95%), Tenax) as well as preparation of different cakes. From the 1st to 10th experiment, siloxane migration into cakes only slightly decreased, with a significant dependence on fat content. Migration never exceeded a level of 21 mgkg~(-1) (3mgdm~2) and was, therefore, well below the overall migration limit of 60mgkg~(-1) (10mgdm~(-2)). However, migration behaviour into simulants differed completely from these results.