In the recycling process of food contact polypropylene, some chemicals will inevitably remain due to incomplete cleaning or degradation, which may threaten food safety.In this paper, gas chromatography-mass spectrometry (GC-MS) and high-performance liquid chromatography-mass spectrometry (HPLC-MS) were used to develop analytical methods for determining the residual of 4 processing additives [bis(2-ethylhexyl) phthalate, Irgafos 168, bis(3,4-dimethylbenzylidene) sorbitol, 2,2′-(octadecylimino)diethanol], degradation products (2,4-di-tert-butylpheno), and 3 volatile compounds (D-limonene, α-terpineol, galaxolide) in recycled polypropylen (rPP).The analytical method was used to analyze 9 market rPP samples, and the results showed that the residue of Irgafos 168 was the highest (998.36 mg/kg).To further study its migration to food in films with different rPP contents, 7 types of films with different contents of rPP (0%, 10%, 25%, 50%, 75%, 90%, 100%, mass fraction) were prepared and then immersed in isooctane, 95% (volume fraction) ethanol, 50% ethanol, and 4% acetic acid at 70 ℃ for 2 hours, respectively.The principal component analysis and the classification and regression tree algorithm were used to analyze the residues.Results indicated that there was no significant difference from virgin polypropylene when the rPP content was less than 25%.This study offers data and protocol support for the safe utilization of rPP for food contact, which is essential for promoting resource recycling and ensuring food safety.
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