Abstract: The analytical methods of ultrasound-assisted solvent extraction (UASE) and solid phase micro-extraction method (SPME) coupled with gas chromatography-tandem mass spectrometry (GC-MS/MS), respectively were developed for the determination of 5 substances of very high concern (SVHC), including N-methylaniline (NMA), N,N-dimethylphylamine (DMA), nonanal, butylated hydroxytoluene (BHT) and benzothiazole (BTZ) in food contact silicone products. These two methods were optimized and evaluated. The results indicated that the USAE-GC-MS/MS method was simpler and more efficient and had wider linear range, higher recovery and precision, which met the requirements of determination. This method was then employed to determine the contents of 5 SVHCs in 29 silicone nipples and 27 molds. The results revealed that the highest content of aldehyde in the nipples was 1 439.85 ng/g and the highest content of BHT in the molds was 4 828.78 ng/g; both NMA and DMA were detected from all samples analyzed. The difference in the contents of these SVHCs in the food contact silicon products was analyzed and their safety was evaluated based on their toxicity, and source and limit requirements. The contents of NMA and DMA were higher in the molds than in the nipples, which may be derived from the organic dye or other additives in the molds. Considering NMA and DMA may pose a risk to human health, the generation of anilines must be controlled by improving the formulation or the process. There was no significant difference in the content of nonanal between the nipples and the molds product. Furthermore, despite the high detection rate, it was still considered that the content of nonanal in the food contact silicon products was within the safe range. Migration experiments and exposure assessments should be carried out for BTZ and BHT in the future.

Key words: food-contact material, silicone rubber, substance of very high concern (SVHC), GC-MS/MS, safety evaluation