Ion-Mobility Quadrupole Time-of-Flight Mass Spectrometry: A Novel Technique Applied to Migration of Nonintentionally Added Substances from Polyethylene Films Intended for Use as Food Packaging

Characterization, hazard identification, and risk assessment of volatile organic compounds in Poly(butylene adipate-co-terephthalate)-based food contact articles

The chemical safety of poly (butylene adipate-co-terephthalate) (PBAT) based food contact articles (FCAs) has aroused increasing toxicological concerns in recent years, but the chemical characterization and associated risk assessment still remain inadequate as it fails to elucidate the distribution pattern and discern the potential genotoxic and carcinogenic hazards of the identified substances. Herein, the volatile organic compounds (VOCs) in 50 batches of PBAT-based FCAs of representative categories and 10 batches of PLA and PBAT pellets were characterized, by which 237 VOCs of 10 chemical categories were identified and exhibited characteristic distribution patterns in the chemical spaces derived from their molecular descriptors. Chemical hazards associated with the identified VOCs were discerned by a hazard-driven classification scheme integrating hazard-related knowledge from multiple publicly available sources, and 34 VOCs were found to bear genotoxic or carcinogenic hazards and to feature higher average molecular weight than the other VOCs. Finally, the Risk and hazard quotient (HQ) calculated as the metrics of risk suggested that all identified VOCs posed acceptable risks (Risk<10-4 or HQ < 1), whereas oxolane, butyrolactone, N,N-dimethylacetamide, 2-butoxyethanol, benzyl alcohol, and 1,2,3-trichloropropane posed non-negligible (Risk>10-6) genotoxic or carcinogenic risk and thus should be of prioritized concern to promote the chemical safety of PBAT-based FCAs.

Strategy proposal using QSAR models to approach mutagenicity assessment of non intentionally added substances in recycled plastic resins

CONTEXT

Transition to the use of recycled plastics raises an issue concerning safety assessment of Non Intentionally Added Substances (NIAS). To assess the mutagenic potential of the recycled polyethylene impurities and to evaluate the need to perform in vitro assays on recycled resins, this study lies in identifying existing NIAS associated with recycled Low/High Density Polyethylene and assessing the mutagenicity data-gaps by employing in silico tools.

METHODS

Quantitative Structure-Activity Relationship (QSAR) models predicting Ames mutagenicity were selected from literature, then NIAS were run to 1/evaluate performances of each model, 2/apply a QSAR strategy on the NIAS molecular space and address data-gaps.

RESULTS

Among the 165 NIAS identified, experimental Ames results were not found for 50 substances while the substances with experimental data were predominantly negatives. No individual model was able to predict all NIAS due to applicability domain limitations. Taking into account 1/calculated performances, 2/availability of applicability domain, 3/description of the Training Set, an Integrated Strategy was founded including Sarpy, Consensus and Protox to extend the applicability domain.

CONCLUSION & PERSPECTIVES

Existing data and predictions generated by this strategy suggest a low mutagenic potential of NIAS. Further investigation is needed to explore other genotoxicity mechanisms.

The analysis of the migration of per and poly fluoroalkyl substances (PFAS) from food contact materials using ultrahigh performance liquid chromatography coupled to ion-mobility quadrupole time-of-flight mass spectrometry (UPLC- IMS-QTOF)

Per-poly fluoroalkyl substances (PFASs) are a group of synthetic fluorine compounds used in food packaging materials to repel water and fats. This study assessed the chemical migration of PFAS from different food contact materials, including cardboard, recycled cardboard, biopolymer, paper and Teflon trays, from various markets. Migration assays were conducted using Tenax® as a food simulant, which was optimized by subjecting it to three consecutive extractions with 3 mL of ethanol within an hour. The resulting extractions were combined and concentrated to 0.5 mL using a nitrogen stream. The analysis was performed using ultrahigh performance liquid chromatography (UPLC) coupled with ion-mobility (IMS) quadrupole-time-of-flight (QTOF) mass spectrometry, which provided a powerful and novel tool for identifying a library of targets containing collision cross section values (CCS) and increasing confidence in subsequent identifications. Eleven PFAS compounds belonging to the family of perfluorocarboxylic acid, perfluorosulfonic acid and perfluorooctanesulfonamidoacetic acid substances (PFCAs, PFSAs and FOSAAs) were found in packaging samples obtained from China, with migrant concentrations ranging 3.2 and 22.3 μg/kg. In contrast, no detectable levels of PFAS were observed in packaging samples obtained in Spain. All trays tested were deemed to be suitable for use as food contact materials due to the fact that their migrant values were lower than 0.025 mg/kg for PFOA and its salts, and lower than a maximum concentration of 1 mg/kg for PFOA-related compounds.

Application of Ion Mobility Spectrometry and the Derived Collision Cross Section in the Analysis of Environmental Organic Micropollutants

Ion mobility spectrometry (IMS) is a rapid gas-phase separation technique, which can distinguish ions on the basis of their size, shape, and charge. The IMS-derived collision cross section (CCS) can serve as additional identification evidence for the screening of environmental organic micropollutants (OMPs). In this work, we summarize the published experimental CCS values of environmental OMPs, introduce the current CCS prediction tools, summarize the use of IMS and CCS in the analysis of environmental OMPs, and finally discussed the benefits of IMS and CCS in environmental analysis. An up-to-date CCS compendium for environmental contaminants was produced by combining CCS databases and data sets of particular types of environmental OMPs, including pesticides, drugs, mycotoxins, steroids, plastic additives, per- and polyfluoroalkyl substances (PFAS), polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), and polybrominated diphenyl ethers (PBDEs), as well as their well-known transformation products. A total of 9407 experimental CCS values from 4170 OMPs were retrieved from 23 publications, which contain both drift tube CCS in nitrogen (DTCCSN2) and traveling wave CCS in nitrogen (TWCCSN2). A selection of publicly accessible and in-house CCS prediction tools were also investigated; the chemical space covered by the training set and the quality of CCS measurements seem to be vital factors affecting the CCS prediction accuracy. Then, the applications of IMS and the derived CCS in the screening of various OMPs were summarized, and the benefits of IMS and CCS, including increased peak capacity, the elimination of interfering ions, the separation of isomers, and the reduction of false positives and false negatives, were discussed in detail. With the improvement of the resolving power of IMS and enhancements of experimental CCS databases, the practicability of IMS in the analysis of environmental OMPs will continue to improve.

Unpacking the complexity of the polyethylene food contact articles value chain: A chemicals perspective

Polyethylene (PE) is the most widely used type of plastic food packaging, in which chemicals can potentially migrate into packaged foods. The implications of using and recycling PE from a chemical perspective remain underexplored. This study is a systematic evidence map of 116 studies looking at the migration of food contact chemicals (FCCs) across the lifecycle of PE food packaging. It identified a total of 377 FCCs, of which 211 were detected to migrate from PE articles into food or food simulants at least once. These 211 FCCs were checked against the inventory FCCs databases and EU regulatory lists. Only 25% of the detected FCCs are authorized by EU regulation for the manufacture of food contact materials. Furthermore, a quarter of authorized FCCs exceeded the specific migration limit (SML) at least once, while one-third (53) of non-authorised FCCs exceeded the threshold value of 10 μg/kg. Overall, evidence on FCCs migration across the PE food packaging lifecycle is incomplete, especially at the reprocessing stage. Considering the EU's commitment to increase packaging recycling, a better understanding and monitoring of PE food packaging quality from a chemical perspective across the entire lifecycle will enable the transition towards a sustainable plastics value chain.

Migration of Dihydroxy Alkylamines and Their Possible Impurities from Packaging into Foods and Food Simulants: Analysis and Safety Evaluation

Alkyl diethanolamines are a group of compounds commonly used as antistatic agents in plastic food packaging materials. These additives and their possible impurities have the ability to transfer into the food; hence, the consumer may be exposed to these chemicals. Recently, scientific evidence of unknown adverse effects associated with these compounds was reported. N,N-bis(2-hydroxyethyl)alkyl (C8-C18) amines as well as other related compounds and their possible impurities were analyzed in different plastic packaging materials and coffee capsules using target and non-target LC-MS methods. N,N-bis(2-hydroxyethyl)alkyl amines, precisely, C12, C13, C14, C15, C16, C17 and C18, 2-(octadecylamino)ethanol and octadecylamine, among others, were identified in most of the analyzed samples. It should be emphasized that the latter compounds are not listed in the European Regulation 10/2011 and 2-(octadecylamino)ethanol was classified as high toxicity according to Cramer rules. Migration tests were carried out in foods and in the food simulants Tenax and 20% ethanol (v/v). The results showed that stearyldiethanolamine migrated into the tomato, salty biscuits, salad and Tenax. Lastly, as a crucial step in the risk assessment process, the dietary exposure to stearyldiethanolamine transferred from the food packaging into the food was determined. The estimated values ranged from 0.0005 to 0.0026 µg/kg bw/day.

Insight into chemical features of migrated additives from plastics and associated risks to estuarine ecosystem

Distinct hydrodynamic conditions created a hotspot of plastic and associated additive pollution within estuaries, which is of considerable scientific interest. However, the effects of specific estuarine weathering (severe mechanical wear, constant turbulence, and strong ultraviolet radiation) on migration of additives remain unclear. Therefore, we investigated the release of migrated plastic additives (MPAs) from three representative plastics, namely floating foam, fishing nets, and packaging bags, under simulated estuarine conditions. Sixty-seven MPAs leached out under the wave scenario, greater than those under the ultraviolet radiation (62) and shoal (40) scenarios. We detected forty MPAs in the plastic bag leachates, whereas fewer MPAs were released from the foam and nets. Several MPAs were peculiar to specific plastics, e.g., antistatic and curing agents in the bag and foam leachates, respectively. Particularly, a suite of nonionic surfactants, octylphenol polyethoxylates (OPEO_n), exhibited outstanding responses in the packaging bag leachates and had elevated toxic potential. OPEO_n significantly inhibited the hatching of zebrafish and caused cardiovascular system disorder and morphological distortions even at environmentally relevant concentrations as in estuaries. Collectively, the leaching of MPAs was significantly enhanced by wave actions, and the plastic leachates, particularly those of plastic bags, can cause detrimental risks to the estuarine ecosystem.

Ultra-high performance liquid chromatography coupled to ion mobility quadrupole time-of-flight mass spectrometry for the identification of non-volatile compounds migrating from 'natural' dishes

Although most new biomaterials for food industry applications are labelled '100% natural fabrication' and 'chemical-free', certain compounds may migrate from those materials to the food, compromising the organoleptic characteristics and safety of the product. In this work, the degree of compound migration from dishes made with four different biomaterials: bamboo, palm leaf, wood and wheat pulp was investigated. Migration tests were carried out using three food simulants, 10% ethanol (simulant A), 3% acetic acid (simulant B), and 95% ethanol (simulant D2). Unequivocal identification of non-intentionally added substances (NIAS) is challenging even when using high-resolution mass spectrometry techniques however, a total of 25 different non-volatile compounds from the migration tests were identified and quantified using Ultra-high performance liquid chromatography coupled to ion mobility quadrupole time-of-flight mass spectrometry (UPLC-IMS-MS). In the bamboo samples three oligomers, cyclic diethylene glycol adipate, 3,6,9,16,19,22-hexaoxabicyclo[22.3.1]-octacosa-1(28),24,26-triene-2,10,15,23-tetrone and 1,4,7,14,17,20-hexaoxacyclohexacosane-8,13,21,26-tetrone exceeded the specified limits of migration.

Safety of recycled plastics and textiles: Review on the detection, identification and safety assessment of contaminants

In 2019, 368 mln tonnes of plastics were produced worldwide. Likewise, the textiles and apparel industry, with an annual revenue of 1.3 trillion USD in 2016, is one of the largest fast-growing industries. Sustainable use of resources forces the development of new plastic and textile recycling methods and implementation of the circular economy (reduce, reuse and recycle) concept. However, circular use of plastics and textiles could lead to the accumulation of a variety of contaminants in the recycled product. This paper first reviewed the origin and nature of potential hazards that arise from recycling processes of plastics and textiles. Next, we reviewed current analytical methods and safety assessment frameworks that could be adapted to detect and identify these contaminants. Various contaminants can end up in recycled plastic. Phthalates are formed during waste collection while flame retardants and heavy metals are introduced during the recycling process. Contaminants linked to textile recycling include; detergents, resistant coatings, flame retardants, plastics coatings, antibacterial and anti-mould agents, pesticides, dyes, volatile organic compounds and nanomaterials. However, information is limited and further research is required. Various techniques are available that have detected various compounds, However, standards have to be developed in order to identify these compounds. Furthermore, the techniques mentioned in this review cover a wide range of organic chemicals, but studies covering potential inorganic contamination in recycled materials are still missing. Finally, approaches like TTC and CoMSAS for risk assessment should be used for recycled plastic and textile materials.

Identification of Nonvolatile Migrates from Food Contact Materials Using Ion Mobility-High-Resolution Mass Spectrometry and in Silico Prediction Tools

The identification of migrates from food contact materials (FCMs) is challenging due to the complex matrices and limited availability of commercial standards. The use of machine-learning-based prediction tools can help in the identification of such compounds. This study presents a workflow to identify nonvolatile migrates from FCMs based on liquid chromatography-ion mobility-high-resolution mass spectrometry together with in silico retention time (RT) and collision cross section (CCS) prediction tools. The applicability of this workflow was evaluated by screening the chemicals that migrated from polyamide (PA) spatulas. The number of candidate compounds was reduced by approximately 75% and 29% on applying RT and CCS prediction filters, respectively. A total of 95 compounds were identified in the PA spatulas of which 54 compounds were confirmed using reference standards. The development of a database containing predicted RT and CCS values of compounds related to FCMs can aid in the identification of chemicals in FCMs.

Prediction of Collision Cross-Section Values for Extractables and Leachables from Plastic Products

The use of ion mobility separation (IMS) in conjunction with high-resolution mass spectrometry has proved to be a reliable and useful technique for the characterization of small molecules from plastic products. Collision cross-section (CCS) values derived from IMS can be used as a structural descriptor to aid compound identification. One limitation of the application of IMS to the identification of chemicals from plastics is the lack of published empirical CCS values. As such, machine learning techniques can provide an alternative approach by generating predicted CCS values. Herein, experimental CCS values for over a thousand chemicals associated with plastics were collected from the literature and used to develop an accurate CCS prediction model for extractables and leachables from plastic products. The effect of different molecular descriptors and machine learning algorithms on the model performance were assessed. A support vector machine (SVM) model, based on Chemistry Development Kit (CDK) descriptors, provided the most accurate prediction with 93.3% of CCS values for [M + H]⁺ adducts and 95.0% of CCS values for [M + Na]⁺ adducts in testing sets predicted with <5% error. Median relative errors for the CCS values of the [M + H]⁺ and [M + Na]⁺ adducts were 1.42 and 1.76%, respectively. Subsequently, CCS values for the compounds in the Chemicals associated with Plastic Packaging Database and the Food Contact Chemicals Database were predicted using the SVM model developed herein. These values were integrated in our structural elucidation workflow and applied to the identification of plastic-related chemicals in river water. False positives were reduced, and the identification confidence level was improved by the incorporation of predicted CCS values in the suspect screening workflow.

Novel insight into dissolved organic nitrogen (DON) transformation along wastewater treatment processes with special emphasis on endogenous-source DON

Knowledge of endogenous-source dissolved organic nitrogen (esDON) produced in wastewater treatment processes is critical for evaluating its potential impacts on receiving waters because esDON is a recognized concern, as it causes eutrophication. However, differentiating esDON from influent residual DON in real wastewater is always a challenge. Here, we deciphered esDON information in DON transformation processes along a full-scale wastewater treatment train by combining multiple chemometric tools with ion-mobility separation quadrupole time-of-flight mass spectrometry (IMS-QTOF MS) analyses. In total, DON became more refractory and compact with shorter carbon chains and fewer nitrogen atoms, and esDON composed a nonnegligible fraction that dominated DON transformation and characteristics. New esDON produced in treatment processes constituted a crucial part (>35.5%) of wastewater DON, and its contributions to wastewater DON are augmented along the train. Evidence of molecular conformations further confirmed dominant roles of esDON in DON characteristics. Moreover, esDON participated in 46.7% of core biochemical reaction networks, explaining the importance of esDON in DON transformation. Our study offers a tool to gain esDON characteristics and transformation mechanisms, and highlights the importance to control esDON for alleviating adverse influences from DON in receiving waters.

A Collision Cross Section Database for Extractables and Leachables from Food Contact Materials

The chemicals in food contact materials (FCMs) can migrate into food and endanger human health. In this study, we developed a database of traveling wave collision cross section in nitrogen (^TWCCS_N2) values for extractables and leachables from FCMs. The database contains a total of 1038 ^TWCCS_N2 values from 675 standards including those commonly used additives and nonintentionally added substances in FCMs. The ^TWCCS_N2 values in the database were compared to previously published values, and 85.7, 87.7, and 64.9% [M + H]⁺, [M + Na]⁺, and [M - H]^- adducts showed deviations <2%, with the presence of protomers, post-ion mobility spectrometry dissociation of noncovalent clusters and inconsistent calibration are possible sources of CCS deviations. Our experimental ^TWCCS_N2 values were also compared to CCS values from three prediction tools. Of the three, CCSondemand gave the most accurate predictions. The ^TWCCS_N2 database developed will aid the identification and differentiation of chemicals from FCMs in targeted and untargeted analysis.

Guidance in selecting analytical techniques for identification and quantification of non-intentionally added substances (NIAS) in food contact materials (FCMS)

There are numerous approaches and methodologies for assessing the identity and quantities of non-intentionally added substances (NIAS) in food contact materials (FCMs). They can give different results and it can be difficult to make meaningful comparisons. The initial approach was to attempt to prepare a prescriptive methodology but as this proved impossible; this paper develops guidelines that need to be taken into consideration when assessing NIAS. Different approaches to analysing NIAS in FCMs are reviewed and compared. The approaches for preparing the sample for analysis, recommended procedures for screening, identification, and quantification of NIAS as well as the reporting requirements are outlined. Different analytical equipment and procedures are compared. Limitations of today's capabilities are raised along with some research needs.

Three-Dimensional Mass Spectral Imaging of Polymers Via Laser-Assisted Micro-Pyrolysis Program with Flowing Atmospheric-Pressure Afterglow Ambient Mass Spectrometry

Herein, a novel diode laser-assisted micro-pyrolysis program (LAMP) technique is demonstrated and coupled with flowing atmospheric-pressure afterglow ambient mass spectrometry for instantaneously profiling polymers and polymer additives. Laser power modulation allows thermal separation of additives and different pyrolysis products, as shown through positive- and negative-mode high-resolution mass spectra and Kendrick mass defect plots of homopolymers, copolymers, polymer blends, and complex polymer samples. LAMP allows much faster temperature control through real-time duty cycle changes and gives significantly better spatial confinement compared to typical resistive heating pyrolysis approaches. Finally, MS imaging, with lateral and depth resolution, is demonstrated for a complex polymer pressure-sensitive adhesive tape sample.

Prediction of Collision Cross Section Values: Application to Non-Intentionally Added Substance Identification in Food Contact Materials

The synthetic chemicals in food contact materials can migrate into food and endanger human health. In this study, the traveling wave collision cross section in nitrogen values of more than 400 chemicals in food contact materials were experimentally derived by traveling wave ion mobility spectrometry. A support vector machine-based collision cross section (CCS) prediction model was developed based on CCS values of food contact chemicals and a series of molecular descriptors. More than 92% of protonated and 81% of sodiated adducts showed a relative deviation below 5%. Median relative errors for protonated and sodiated molecules were 1.50 and 1.82%, respectively. The model was then applied to the structural annotation of oligomers migrating from polyamide adhesives. The identification confidence of 11 oligomers was improved by the direct comparison of the experimental data with the predicted CCS values. Finally, the challenges and opportunities of current machine-learning models on CCS prediction were also discussed.

Trace analysis of multiple synthetic phenolic antioxidants in foods by liquid chromatography-tandem mass spectrometry with complementary use of electrospray ionization and atmospheric pressure chemical ionization

This study presented a universal LC-MS/MS method for trace analysis of multiple synthetic phenolic antioxidants (SPAs) in foods by complementary use of electrospray ionization (ESI) and atmospheric pressure chemical ionization (APCI). The analytes included not only the well-known BHT and BHA but also 18 high molecular weight SPAs. The method utilized APCI to achieve sensitive analysis of BHT, Irganox 1010, Irganox 330, and Irganox 3125 based on the finding that APCI significantly improved the sensitivity of these weakly acidic or slightly polar SPAs, and utilized ESI to obtain sensitive analysis of other SPAs. Additionally, the method avoided background contamination by using effective measures including installation of a trapping column in the LC system. Method performance assessment showed satisfactory sensitivity, linearity, accuracy, and precision for analysis of SPAs in vegetable oil, milk powder, and baby fruit puree. Method application revealed widespread contamination of foods with BHT, Irganox 1010, and Irganox 1076.

The application of ion mobility time of flight mass spectrometry to elucidate neo-formed compounds derived from polyurethane adhesives used in champagne cork stoppers

Polyurethane adhesives are used to bond agglomerated cork and natural disk cork to produce cork stoppers that are used in champagne bottles. These adhesives are manufactured by reacting polyols with an excess of diisocyanates. Isocyanates are highly reactive compounds that have a propensity to form non-intentionally added substances (NIAS) in the end product. In this work, ion mobility-time of flight-mass spectrometry was used to elucidate such NIAS, through the comparison of accurate mass spectra with the fragmentation patterns of proposed candidates. Twelve neo-formed compounds, including amines, amides and urethanes, resulting from the reaction of isocyanates with acetic acid and ethanol used as food simulants, were identified. Additionally, markers from champagne vs. champagne after its exposure to the adhesive were investigated using the supervised multivariate analysis method of Orthogonal Projection to Latent Structures - Discriminant Analysis. Four neo-formed compounds, resulting from the reaction of diisocyanates with malic acid or tartaric acid contained in the champagne, were identified for the first time in this work. All of the compounds identified were subsequently quantified using ultra-high pressure liquid chromatography coupled to a triple quadrupole mass spectrometer. Limits of detection were below 5 μg/kg in the food simulants and below 30 μg/kg in champagne samples. Migration levels ranged from 70 to 721 μg/kg, with most of them exceeding the specific migration limit established for Cramer class III compound (90 μg/kg).

Migration of (non-) intentionally added substances and microplastics from microwavable plastic food containers

Microwavable plastic food containers (MPFCs) are extensively used for food storage, cooking, rapid heating and as take-out containers. There is an urgent need to investigate whether MPFCs pose potential health risks, as a result of the migration of chemicals into foods. Herein, 42 intentionally added substances (IAS) and > 100 non-IAS (NIAS) migrating from MPFCs were identified in food simulants according to Regulation (EU). The migration of major IAS and NIAS was higher in 95% ethanol compared to other simulants, and gradually decreased following repeated use. NIAS, including Cramer class III toxic compounds, such as PEG oligomers of N,N-bis(2-hydroxyethyl) alkyl(C8-C18)amines, isomers of hexadecanamide and oleamide, and Irgafos 168 OXO were detected and exceeded the recommended limits in some MPFCs. Furthermore, microplastics (MPs) were detected with high values of over one million particles/L in some MPFCs in a single test, and migration behaviors of MPs in different MPFCs were diverse. Surprisingly, this rigorous migration might result in an annual intake of IAS/NIAS up to 55.15 mg and 150 million MPs particles if take-out food was consumed once a day. Multi-safety evaluation studies on the migration of various chemicals from MPFCs to foodstuffs during food preparation should be assessed.

The migration of NIAS from ethylene-vinyl acetate corks and their identification using gas chromatography mass spectrometry and liquid chromatography ion mobility quadrupole time-of-flight mass spectrometry

An exhaustive migration study of eight corks, made of ethylene-vinyl acetate, was carried out to identify any non-volatile and volatile compounds using an untargeted approach. The challenge associated with the structural elucidation of unknowns was undertaken using both ultra-high-performance liquid chromatography coupled to an ion-mobility separation quadrupole-time of flight mass spectrometer and gas chromatography mass spectrometry. A total of fifty compounds were observed to migrate from the corks, and among these additives such as antioxidants (Butyl 4-hydroxybenzoate, Irganox 1010, Irganox 1075, Irgafos 168 and BHT) or lubricants (EBO and octadecanamide, N,N'-1,2-ethanediylbis-) were identified. A high proportion (84%) of the detected compounds was non-intentionally added substances (NIAS), and included several cyclic oligomers with different chain sequences. NIAS, such as 2,6-bis(1,1-dimethylethyl)-4-ethyl and 7,9-ditert-butyl-1-oxaspiro[4.5]deca-6,9-diene-2,8-dione, break-down products, including hexa-, hepta- and nonadecanamide, N,N'-1,2-ethanediylbis-, and oxidation products were also identified. One cork was found to be unsuitable for use as a food contact material.

Safety of Plastic Food Packaging: The Challenges about Non-Intentionally Added Substances (NIAS) Discovery, Identification and Risk Assessment

Several food contact materials (FCMs) contain non-intentionally added substances (NIAS), and most of the substances that migrate from plastic food packaging are unknown. This review aimed to situate the main challenges involving unknown NIAS in plastic food packaging in terms of identification, migration tests, prediction, sample preparation, determination methods and risk assessment trials. Most studies have identified NIAS in plastic materials as polyurethane adhesives (PU), polyethylene terephthalate (PET), polyester coatings, polypropylene materials (PP), multilayers materials, plastic films, polyvinyl chloride (PVC), recycled materials, high-density polyethylene (HDPE) and low-density polyethylene (LDPE). Degradation products are almost the primary source of NIAS in plastic FCMs, most from antioxidants as Irganox 1010 and Irgafos 168, following by oligomers and side reaction products. The NIAS assessment in plastics FCMs is usually made by migration tests under worst-case conditions using food simulants. For predicted NIAS, targeted analytical methods are applied using GC-MS based methods for volatile NIAS and GC-MS and LC-MS based methods for semi- and non-volatile NIAS; non-targeted methods to analyze unknown NIAS in plastic FCMs are applied using GC and LC techniques combined with QTOF mass spectrometry (HRMS). In terms of NIAS risk assessment and prioritization, the threshold of toxicological concern (TTC) concept is the most applied tool for risk assessment. Bioassays with sensitive analytical techniques seem to be an efficient method to identify NIAS and their hazard to human exposure; the combination of genotoxicity testing with analytical chemistry could allow the Cramer class III TTC application to prioritize unknown NIAS. The scientific justification for implementing a molecular weight-based cut-off (<1000 Da) in the risk assessment of FCMs should be reevaluated. Although official guides and opinions are being issued on the subject, the whole chain's alignment is needed, and more specific legislation on the steps to follow to get along with NIAS.

The use of ion mobility time-of-flight mass spectrometry to assess the migration of polyamide 6 and polyamide 66 oligomers from kitchenware utensils to food

Oligomers, are, in general, unknown components of the polymer. These oligomers can migrate from the polymer into the food and become a non-intentionally added substance to the food. In this work, ion mobility time-of-flight mass spectrometry has been used to identify oligomers migrating from kitchenware. The structure elucidation of oligomers from polyamide 6 and polyamide 66 was achieved through the analysis of accurate m/z values of adducts and collision cross section values of precursor ions together with high-energy fragmentation patterns. Additionally, a method to extract oligomers from sunflower oil, cooked beans, soup and whole milk has been developed. Extraction recoveries ranged from 87 to 102% and limits of detection were from 0.03 to 0.11 mg/kg. It was observed that the migration from kitchenware to real food was below the specified migration limit of 5 mg/kg. However, this limit was exceeded for food simulants, which therefore overestimated the oligomer migration.

Non-targeted analysis and risk assessment of non-volatile compounds in polyamide food contact materials

Small molecules in food contact materials may migrate into food during their contact. To extensively analyze the migrants, non-targeted screening is needed to detect the migrants. The migrants' detection is difficult because of the complexity and the trace amount of the migrants. In this work, the dissolution precipitation method was used to extract small molecules in Polyamide (PA) kitchenware. The extract solutions were screened by ultra-performance liquid chromatography-quadrupole time-of-flight-mass spectrometry (UPLC-QTOF-MS) for non-targeted analysis and 64 different small molecules in materials were identified through the screening of a self-built database. Then, migration tests were performed to analyze migrants in food simulants. It suggests that the abundance of PA oligomers was the highest in migrants. The risk assessment of migrants revealed that the exposure of most migrants was at a safer level unlike the exposure of PA oligomers that exceeded their threshold of toxicological concern (TTC).

Identification of chemicals in a polyvinyl chloride/polyethylene multilayer film by ultra-high-performance liquid chromatography/quadrupole time-of-flight mass spectrometry and their migration into solution

An ultra-high-performance liquid chromatography/quadrupole time-of-flight mass spectrometry (UPLC-QTOF/MS) method was employed for chemical identification in a commercial polyvinyl chloride/polyethylene (PVC/PE) multilayer film. Over 30 chemicals from different layers (PE layer, PVC layer, and adhesive layer) of the film were identified and were classified into 6 groups, including antioxidants, plasticizers, slip agents, antistatic agents, adhesive components, etc. Special attention was placed on the analysis of some non-intentionally added substances and oligomers in adhesive. Based on the identification results, six additives (all from PE layer) were selected and their migration behaviors were investigated via one-sided contact migration test. The migration test was performed by exposing the PE side of the film to different simulating solutions (water, 40% ethanol, and 95% ethanol) at 40°C, as well as recording the migration level as a function of time. No obvious migration was found into water for all additives, while the migration into 40% and 95% ethanol followed Fickian diffusion behavior, and could be described by Fick's diffusion equation. Diffusion coefficients derived from the equation were in a range of 10^-13 to 10^-10 cm²/s and were dependent on the type of additive and solution.

Oleamide, a Bioactive Compound, Unwittingly Introduced into the Human Body through Some Plastic Food/Beverages and Medicine Containers

The purpose of the study was to investigate the migration of oleamide, a polymer lubricant, and a bioactive compound, from various plastic, marketed containers for food/beverages and medicines into polymer contact liquid. Methanol, food/medicine simulants or real samples were used to extract polymer leachables and extractables. Migrated oleamide into polymer contact liquids was determined by ultra-high performance liquid chromatography coupled to mass spectrometry (UHPLC-MS). The concentration of oleamide in the extracts of medicinal and insulin syringes was 7351 ng mL^-1 and 21,984 ng mL^-1, respectively. The leachates of intravenous (i.v.) infusion bottle, medicinal and insulin syringes contained 17 ng mL^-1, 12 ng mL^-1 and 152 ng mL^-1, respectively. Oleamide in the extracts of dummies ranged from 30 to 39 ng mL^-1, while in the leachates of baby bottles, from 12 to 23 ng mL^-1. Leachates of soft drink bottles contained from 6 to 15 ng mL^-1 oleamide, milk bottles from 3 to 9 ng mL^-1, liquid yogurt bottles 17 ng mL^-1 and water bottles from 11 to 18 ng mL^-1. Bottled real matrices of oil and milk contained oleamide in the range from 217 to 293 ng mL^-1. Moreover, the source of migrated oleamide (e.g., containers, caps, other parts) was identified. Oleamide is listed in the current EU regulations without a specific migration limit. Accordingly, these values are considered of no concern, unless future toxicological studies prove the opposite.