Identification And Risk Assessment Of Non-volatile Migrants In Plastic Food Contact Materials

Plastics are widely used as food contact materials due to their excellent mechanical properties,processing properties,barrier properties,light weight,and ease of transportation.However,when food contact materials come into contact with food,the small molecular substances in the materials will migrate into the food.So the materials used for food contact need to be evaluated for safety to ensure that they will not harm consumers' health.The premise of the safety assessment of plastic food contact materials is the need to accurately determine the migration.UPLC-MS technology has the advantages of high sensitivity,high separation capacity,fast and high efficiency,etc.,and is widely used in the research of migration in food contact materials.This article is based on ultra-high performance liquid chromatography tandem quadrupole time-flight mass spectrometry(UPLC-QTOF-MS)technology for screening and risk assessment of non-volatile migration in two food contact materials(PET and PA).The results obtained are as follows:(1)According to the EU 10/2011 regulations,PET bottles were subjected to migration tests.The PET bottles were subjected to three food simulants(3%(w/v)acetic acid,10%and 95%(v/v)ethanol)for 10 days;The PET material can also be used as a filtrate bag,so the PET filtrate bag is soaked in two simulated liquids(isopropyl alcohol/water=1/1 and 95%(v/v)ethanol)at 60? for two days.Screen the PET oligomers in the simulated solution by the non-target acquisition mode of UPLC-QTOF-MS.According to the obtained fragment mass spectrum and the screening of the self-built database,the oligomers were identified.As a result,18 kinds of PET oligomers were found in samples.Toxtree and TEST toxicology software were used to evaluate the toxicity of PET oligomers.(2)In order to explore the source of PET oligomers,three samples of PET bottle production,raw material particles,semi-finished preforms and finished bottles were collected based on the supply chain.The oligomers in the samples were extracted by dissolution precipitation method,and 31 oligomers in three samples were screened by UPLC-QTOF-MS.In the traceability of PET oligomers,it was found that the area of oligomers between bottles and particles were linearly related.Oligomers came from both raw material particles and thermal degradation products of the polymer matrix in the PET bottle manufacturing process,and the former is its main source.For regulatory purposes,the amount of oligomer in the bottle can be controlled by controlling the amount of oligomer in the raw material.(3)The dissolution precipitation method was used to extract small molecule potential migrants in five kinds of polyamide kitchen utensils.A total of 64 small molecule substances were identified by the non-target scanning mode method of UPLC-QTOF-MS.The migration test of five samples in three food simulants(3%(w/v)acetic acid,10%and 95%(v/v)ethanol)showed that PA oligomers had the highest migration value in 36 kinds of migrants.Based on the EU 10/2011 regulations,the exposure of migrants was calculated,and the risk assessment was carried out in conjunction with the safety threshold.The results showed that the exposure of most migrants was below its safety threshold,but the exposure of PA oligomers exceeded its TTC threshold,indicating that the migration of PA oligomers into foods at high levels may harm consumption health.(4)The migration behavior of PA oligomers in the PA66 shovel was studied by UPLC-MS.The migration test was conducted at 60?,using 10%and 95%(v/v)ethanol two kinds of food simulants.Based on Fick's second law,the diffusion coefficients of the three PA66 oligomers obtained by the experiment were calculated,the results show that oligomers with smaller molecular weight and volume are more likely to migrate out of the polymer.And the diffusion coefficients of the oligomers were predicted using the Piringer and Welle models.The results show that the Piringer model can be used to predict the migration of PA oligomers in low-alcohol foods.The values of the existing parameters(a,b,c,d)in the Welle model are not suitable for predicting the migration of PA oligomers.