Advanced separation of mineral oil aromatic hydrocarbons by number of aromatic rings using donor-acceptor-complex chromatography to extend on-line coupled liquid chromatography-gas chromatography.

An automated implementation for a subfractionation of mineral oil aromatic hydrocarbons (MOAH) into a mono-/di-aromatic fraction (MDAF) and a tri-/poly-aromatic fraction (TPAF) is presented, which is highly demanded by the European Food Safety Authority (EFSA) respecting the genotoxic and carcinogenic potential of MOAH. For this, donor-acceptor-complex chromatography (DACC) was used as a selective stationary phase to extend the conventional instrumental setup for the analysis of mineral oil hydrocarbons via on-line coupled liquid chromatography-gas chromatography-flame ionization detection (LC-GC-FID). A set of six new internal standards was introduced for the verification of the MOAH fractionation and a quantification of MDAF and TPAF, respectively. The automated DACC approach was applied to representative petrochemical references as well as to food samples, such as rice and infant formula, generally showing well conformity with results obtained by state-of-the-art analysis using two-dimensional GC (GCxGC). Relative deviations of DACC/LC-GC-FID compared to GCxGC-FID methods regarding the ≥ 3 ring MOAH content ranged between -50 and +6 % (median: -2 %, all samples, only values above limit of quantification). However, crucial deviations mainly result from "border-crossing" substances, e.g., dibenzothiophenes or partially hydrogenated MOAH. These substances can cause overestimations of ≥ 3 ring MOAH fraction during GCxGC analysis due to co-elution, which is mostly avoided using the DACC approach. Furthermore, the DACC approach can help to minimize underestimations of toxicologically relevant ≥ 3 ring MOAH caused by an unavoidable loss of MOAH during epoxidation, since natural olefins, such as terpenes, predominantly elute in MDAF, which was exemplarily shown for an olive oil and a terpene reference. The presented approach can be implemented easily in existing LC-GC-FID setup for an automated and advanced screening of MOAH to lower the need for elaborate GCxGC analysis also in routine environments.

Effect of relative humidity on the desorption of odour-active volatile organic compounds from paper and board: sensory evaluation and migration to Tenax®.

Paper and board are used for packaging of moist as well as dry food. According to Regulation (EC) No. 1935/2004, food contact materials (FCM) must not bring about a deterioration in the organoleptic characteristics of foodstuffs. For testing the transfer of off-flavour (taint) from packaging to food via the gas phase (DIN EN 1230-2), relative humidity (rH) has to be adjusted. In contrast, rH is neither taken into account when testing the odour (DIN EN 1230-1), nor in chemical migration of volatile organic substances (VOC) onto the adsorbent Tenax® (DIN EN 14338). In this work, effect of different rHs on the desorption of VOC from paper and board was investigated by GC-MS analysis as well as by human sensory tests. Raising humidity led to an increase in VOC transfer, which was observed by increasing peak areas as well as the detection of more substances in GC-MS. Analytical results were in line with human sensory tests. The odour profile of the paper at 33 and 58% rH was described as cardboard-like, sweet and smoky. Impact substances for these olfactory impressions were (E)-2-nonenal, vanillin and 2-methoxyphenol as identified by GC with an olfactory detection port (GC-ODP). The increase to 75 and 100% rH resulted in the additional perception of cheesy/sweaty and fatty/rancid impressions, which were primarily caused by short-chain fatty acids and di-unsaturated aldehydes.

Migration of oligomers from Tritan™ copolyester: application of hydrolysis for overall oligomer determination.

Tritan™ (a kind of glycol-modified polycyclohexylene dimethylene terephthalate) is a novel copolyester mainly in use for the production of sports bottles and food storage containers. Oligomers in three food-grade Tritan™ samples were identified after dissolution-precipitation by high performance liquid chromatography with diode array detection and mass spectrometry and quantified after alkaline hydrolysis to the monomers. The obtained overall oligomer content <1000 Da determined by hydrolysis ranged from 7.2 to 10.6 mg/g material. Three consecutive migration experiments were performed according to the Commission Regulation (EU) No 10/2011. Oligomer migration values decreased from first to third migration during all simulations. Less than 25 µg/kg (third migrate) were detected in bottle migrates when tested under room temperature storage conditions (40 °C, 24 h) with simulants 3% acetic acid, 20 and 50% ethanol and during hot-fill testing (70 °C, 2 h) with simulants 3% acetic acid and 20% ethanol, respectively, while 170 µg/kg were determined in 50% ethanol after migration at 70 °C for 2 h. Food storage containers that were labelled as microwave-suitable by the supplier were tested according to the Joint Research Centre recommendations for microwave dishware. A strong deformation of the containers as well as a loss of transparency were observed during the tests (100 °C, 2 h with 10% ethanol and 3% acetic acid in an autoclave, 121 °C, 30 min with sunflower oil), questioning the suitability of the material for microwave applications. Maximum oligomer migration was 379 µg/kg during the third migration (sunflower oil at 121 °C for 30 min). Based on the migration data and an in silico oligomer evaluation according to the threshold of toxicological concern concept, no exceedances of daily thresholds for oligomers are expected from a proper use of Tritan™ drinking bottles, even with hot drinks.

Evaluating the food safety and risk assessment evidence-base of polyethylene terephthalate oligomers: A systematic evidence map.

BACKGROUND: The presence of polyethylene terephthalate (PET) oligomers in food contact materials (FCMs) is well-documented. Consumers are exposed through their migration into foods and beverages; however, there is no specific guidance for their safety evaluation. OBJECTIVES: This systematic evidence map (SEM) aims to identify and organize existing knowledge and associated gaps in hazard and exposure information on 34 PET oligomers to support regulatory decision-making. METHODS: The methodology for this SEM was recently registered. A systematic search in bibliographic and gray literature sources was conducted and studies evaluated for inclusion according to the Populations, Exposures, Comparators, Outcomes, and Study type (PECOS) framework. Inclusion criteria were designed to record hazard and exposure information for all 34 PET oligomers and coded into the following evidence streams: human, animal, organism (non-animal), ex vivo, in vitro, in silico, migration, hydrolysis, and absorption, distribution, metabolism, excretion/toxicokinetics/pharmacokinetics (ADME/TK/PK) studies. Relevant information was extracted from eligible studies and synthesized according to the protocol. RESULTS: Literature searches yielded 7445 unique records, of which 96 were included. Data comprised migration (560 entries), ADME/TK/PK-related (253 entries), health/bioactivity (98 entries) and very few hydrolysis studies (7 entries). Cyclic oligomers were studied more frequently than linear PET oligomers. In vitro results indicated that hydrolysis of cyclic oligomers generated a mixture of linear oligomers, but not monomers, potentially allowing their absorption in the gastrointestinal tract. Cyclic dimers, linear trimers and the respective smaller oligomers exhibit physico-chemical properties making oral absorption more likely. Information on health/bioactivity effects of oligomers was almost non-existent, except for limited data on mutagenicity. CONCLUSIONS: This SEM revealed substantial deficiencies in the available evidence on ADME/TK/PK, hydrolysis, and health/bioactivity effects of PET oligomers, currently preventing appropriate risk assessment. It is essential to develop more systematic and tiered approaches to address the identified research needs and assess the risks of PET oligomers.

Oligomers in polybutylene terephthalate for food contact-strategies on identification, quantification, and risk assessment.

Oligomers are a significant group of migrating substances from food contact materials made of polyesters like polybutylene terephthalate (PBT). Twenty-three cyclic and linear oligomers with different end groups including olefin-terminated oligomers, which are associated with thermal stress of the material, were tentatively identified in PBT extracts by high-performance liquid chromatography with mass spectrometry and diode array detection. Quantification approaches based on chromophore concentration, relative response factors, and overall oligomer determination after hydrolysis to the monomer terephthalic acid were employed. An exhaustive extraction of thirteen PBT samples yielded an overall oligomer content of 1.87-6.10 mg/g material (sum of individual oligomers < 1,000 Da) with a predominant content of cyclic over linear oligomers. Migration experiments were performed according to Regulation (EU) No. 10/2011 using the official food simulants as well as cows' milk. A total of 218 µg cyclic oligomers/L milk were detected in the third migrate relevant for risk assessment of repeated-use articles under hot-fill conditions (70 °C, 2 h). The official food simulant for milk, 50% ethanol, was found to overestimate the actual migration into milk by a factor of four. Frying conditions using sunflower oil as the food simulant (200 °C, 10 min) resulted in a migration of 7.5 mg cyclic oligomers/kg oil. The exposure to migrating oligomers is critical in some scenarios when evaluated by the threshold of toxicological concern concept; however, the toxicological evaluation poses a challenge due to the possible hydrolysis of cyclic oligomers in the human gastrointestinal tract. Our experiments display the need for a toxicological evaluation of PBT oligomers because the migration of cyclic oligomers is expected to exceed the current in silico-based thresholds under foreseeable conditions of use.

Evaluating the food safety and risk assessment evidence-base of polyethylene terephthalate oligomers: Protocol for a systematic evidence map.

BACKGROUND: Polyethylene terephthalate (PET) oligomers are ubiquitous in PET used in food contact applications. Consumer exposure by migration of PET oligomers into food and beverages is documented. However, no specific risk assessment framework or guidance for the safety evaluating of PET oligomers exist to date. AIM: The aim of this systematic evidence map (SEM) is to identify and organize existing knowledge clusters and associated gaps in hazard and exposure information of PET oligomers. Research needs will be identified as an input for chemical risk assessment, and to support future toxicity testing strategies of PET oligomers and regulatory decision-making. SEARCH STRATEGY AND ELIGIBILITY CRITERIA: Multiple bibliographic databases (incl. Embase, Medline, Scopus, and Web of Science Core Collection), chemistry databases (SciFinder-n, Reaxys), and gray literature sources will be searched, and the search results will be supplemented by backward and forward citation tracking on eligible records. The search will be based on a single-concept PET oligomer-focused strategy to ensure sensitive and unbiased coverage of all evidence related to hazard and exposure in a data-poor environment. A scoping exercise conducted during planning identified 34 relevant PET oligomers. Eligible work of any study type must include primary research data on at least one relevant PET oligomer with regard to exposure, health, or toxicological outcomes. STUDY SELECTION: For indexed scientific literature, title and abstract screening will be performed by one reviewer. Selected studies will be screened in full-text by two independent reviewers. Gray literature will be screened by two independent reviewers for inclusion and exclusion. STUDY QUALITY ASSESSMENT: Risk of bias analysis will not be conducted as part of this SEM. DATA EXTRACTION AND CODING: Will be performed by one reviewer and peer-checked by a second reviewer for indexed scientific literature or by two independent reviewers for gray literature. SYNTHESIS AND VISUALIZATION: The extracted and coded information will be synthesized in different formats, including narrative synthesis, tables, and heat maps. SYSTEMATIC MAP PROTOCOL REGISTRY AND REGISTRATION NUMBER: Zenodo: https://doi.org/10.5281/zenodo.6224302.

Styrene-acrylonitrile-copolymer and acrylonitrile-butadiene-styrene-copolymer: a study on extractable and migratable oligomers.

Styrene-acrylonitrile-copolymer (SAN) and acrylonitrile-butadiene-styrene-copolymer (ABS) are gaining in importance as food contact materials. Oligomers and other non-intentionally added substances can migrate into foodstuffs. Five SAN and four ABS samples from the German market and manufacturers were extracted and the extractable oligomers were characterised by high performance liquid chromatography-mass spectrometry/ultraviolet detection/chemiluminescence nitrogen detection/fluorescence detection and gas chromatography-mass spectrometry. Trimers, formed from acrylonitrile and styrene units, were determined to be the dominating group of extractable oligomers in SAN and ABS in concentrations of about 4900-15800 mg/kg material. Furthermore, styrene-acrylonitrile dimers, styrene oligomers, styrene monomer and ethylbenzene were identified in the sample extracts. Migration testing with three consecutive migrations for multiple use articles was performed for two SAN articles. Migration of trimers into water, 3% acetic acid, 10% and 20% ethanol under hot-fill conditions (70°C, 2 h) was not detectable above 9 µg/dm2, while 50% ethanol acting as a food simulant for milk (124 µg/dm2 trimers during the third migration) was shown to overestimate the actual migration into milk (< 11 µg/dm2 trimers at 70°C, 2 h). 2-Amino-3-methyl-1-naphthalenecarbonitrile (AMNC), an oligomer degradation product and a primary aromatic amine, was detected in all material sample extracts (0.3-17.1 mg/kg material) and was released into food simulants in low amounts (< 0.014 µg/dm2 during the third migration into 50% ethanol at 70°C, 2 h).

Bio-based and compostable polyesters in food contact: analysis of monomers and (in)organic fillers.

Polyesters labelled as bio-based or compostable are increasingly common among the 'bioplastics' in use as food contact materials (FCM). The knowledge of material composition is mandatory to predict potential leachable oligomers as well as to partly evaluate the correctness of the label 'bioplastic', which is used for promotional purposes. The composition of (bio)polyesters can be determined by alkaline hydrolysis of the entire material and subsequent analysis of the monomers via high-performance liquid chromatography with diode array detection and GC-MS detection. Thirty-three frequently used monomers (polycarboxylic acids, hydroxy carboxylic acids, polyols) including highly polar monomers such as lactic acid were analysed with detection limits below 10 g/kg of the material. Lactic acid enantiomer elucidation was performed using an enzyme assay. The content of non-hydrolysable residue was determined gravimetrically after hydrolysis, and the inorganic residue after washing. The composition of 12 polyesters mostly in food contact, labelled as bio-based or compostable and sampled from the market was elucidated recovering 92-101% of the total mass by summing up the determined monomers and non-polyester contents. Seven different monomers were detected in the 12 samples (up to four different monomers per sample), lactic acid being the most common (9 samples) with contents ranging from a minor component (about 11 mol%) up to the only monomer found in the material. The ratio of d- to l-lactic acid ranged from 0.3:99.7 to 4.7:95.3 (w/w). The non-hydrolysable (in)organic residue was quantified in amounts of up to 390 g/kg. Overall, the presented analytical protocol is a fundamental tool helping both to verify the appropriateness of labelling as biopolyesters as well as to predict potential leachables such as oligomers during an FCM risk assessment.

Linear and cyclic oligomers in PET, glycol-modified PET and Tritan™ used for food contact materials.

Polyesters are commonly used as food contact materials. During manufacture of polyesters different low molecular mass oligomers (<1000 Da) are formed in the polymer melt. These so-called non-intentionally added substances (NIAS) are potential migrants into foods. In this work, different polyester samples made of polyethylene terephthalate (PET), glycol-modified PET (PETG) and Tritan™ were investigated on their qualitative and quantitative oligomer composition. The analysis of acetonitrile extracts by HPLC-DAD/ESI-MS revealed the presence of about 100 linear (different combinations of hydroxyl-, carboxyl-, methyl ester end groups) and cyclic oligomers depending on the main and co-monomers. The identified oligomers were quantified in different extracts and after reprecipitation by HPLC-DAD using bis-hydroxyethylene terephthalate (BHET) as external standard. The amount of oligomers isolated by reprecipitation ranged between 0.80 and 3.4% in the respective polyester. Cyclic oligomers generally made up 90% or more of the isolated oligomers. Compared to the exhaustive extracts the leaching of oligomers into 20% ethanol (1 h, 60 °C) resulted in a considerable change of the oligomer distribution with a predominant detection of linear oligomers. This suggests linear oligomers to be relevant for migration into aqueous foods despite the dominant amount of extractable cyclic oligomers in polyesters. Analysis of the extractable oligomers of a PET preform and a PETG container and their corresponding raw material pellets revealed that the injection moulding process did not significantly change the amount of cyclic oligomers but did increase the amount of low molecular mass linear oligomers about twofold.

Characterisation, release and migration of phenolic compounds from resoles used in polyester-phenol coatings intended for food contact materials.

Resoles are multifarious pre-polymeric resins produced by the condensation of basic chemicals phenols, formaldehyde and optionally aliphatic alcohols like butanol. They are widely used as cross-linkers to form resistant internal coatings on metal surfaces of cans, containers or closures. Although the application of resoles is common in food contact, usually little is known about their exact composition, the toxicological hazards of their individual constituents and the migration of phenolic compounds, e.g., of the potentially endocrine-disrupting chemical bisphenol F. Our study fills major gaps of knowledge in risk assessment, using the example of a two-layer polyester-phenol coating system, which is based on three different resoles and is commercially used for closures of infant food glass jars. Various analytical approaches, namely size-exclusion chromatography, nuclear magnetic resonance spectroscopy, liquid chromatography coupled to mass spectrometry, fluorescence and diode array detection as well as gas chromatography-mass spectrometry were evaluated to quantitatively characterise resoles. Additionally, derivatisation with dansyl chloride as well as Folin-Ciocalteu colorimetric assay was adapted first times to determine the total phenol content from technical resoles. Individual mono- and bisphenols were determined in resoles up to about 120 mg/g, while the concentration of bisphenol F isomers was below 10 mg/g. Migration from the coating system was determined after sterilisation (121°C, 1 h, 20% ethanol). Results were ~2 µg/dm2 for identified individual mono-phenols like 2-hydroxybenzyl alcohol and up to ~120 µg/dm2 for total phenolic compounds, representing approximately 7% of the overall migration. The migration of bisphenol F isomers was negligible below 0.3 µg/dm2. Potential exposure to migrating phenols was assessed based on the threshold of toxicological concern concept to be significantly below for individual phenols and in the same order of magnitude for total phenols compared to the respective thresholds calculated for infants.

Release and migration of cyclic polyester oligomers from bisphenol A non-intent polyester-phenol-coatings into food simulants and infant food - a comprehensive study.

Coatings for cans or closures are essential to protect the metal from corrosion and the food from migration of hazardous metal ions. Since coatings are no inert materials, they can release substances of potential health concern into food. In the present study, a comprehensive analysis is presented for a complex two-layered polyester-phenol-coating commercially used for metal closures of complementary infant food in sterilised glass jars. Focussed on the identity and migration of cyclic polyester oligomers as a kind of predictable non-intentionally added substances, polyester resin raw materials (n = 3) as well as individual coating layers (n = 3) were characterised by several analytical strategies (size exclusion chromatography, high-performance liquid chromatography mass spectrometry, diode array detection, charged aerosol detection, monomer determination after alkaline hydrolysis, overall migrate). The main polyester monomers were terephthalic acid, isophthalic acid, trimellitic acid, ethylene glycol, diethylene glycol, neopentylglycol, 2-methyl-1,3-propanediol, 1,4-butanediol and tricyclodecanedimethanol. The coatings were extracted with solvents acetonitrile and ethanol (24 h, 60°C), food simulants 50% ethanol, 20% ethanol and water (1 h, 121°C) as well as homemade and commercial baby food (1 h, 121°C). The released total polyester content determined by alkaline hydrolysis ranged from 288 µg/dm2 (water, 1 h, 121°C) to 6154 µg/dm2 (acetonitrile, 24 h, 60°C). However, individual cyclic oligomers, mainly dimers, were released from the coating to up to about 140 µg/dm2. Migration into infant food was best represented by the food simulants water (up to 1% fat) and 20% ethanol (up to 5% fat). Cyclic polyester oligomers are classified as Cramer III substances by the threshold of toxicological concern concept associated to an exposure threshold of 1.5 µg/kg body weight per day. Exposure to cyclic polyester oligomers might be a potential concern for highly exposed infants.

Determination of color developers replacing bisphenol A in thermal paper receipts using diode array and Corona charged aerosol detection-A German market analysis 2018/2019.

Thermal papers (e.g. point of sale receipts, adhesive labels, tickets) significantly contribute to contamination of paper material cycles and the environment with substances of (eco-) toxicological concern. In particular, they contain color developers like endocrine disrupting bisphenols in typical concentrations of about 1-2 percent per weight (wt%). Bisphenol A (BPA) was used as the common color developer over the last decades, but it will be restricted for thermal paper application in the European Union to a limit of 0.02 wt% from 2020 onwards. Consequently, a variety of BPA substituents such as bisphenol S (BPS) and its derivatives gain importance in thermal paper application. In this study, a rapid, reliable and cost-effective method for identification and quantification of BPA, alternative color developers and related substances like sensitizers is presented based on HPLC separation coupled with diode array detection (DAD) and Corona charged aerosol detection (CAD). Quantification was performed with regard to the intended use of the substances in thermal papers. Besides traditional UV external calibration using reference standards, alternative quantification approaches, in particular UV chromophore concentration for BPS derivatives and CAD universal response technique for low-volatile color developers, were applied and compared in order to allow quantification without reference substances. A market analysis for intended used color developers and sensitizers was performed on thermal paper samples (n = 211) collected in Germany during 2018 and 2019. Pergafast 201 (in 41.7% of the samples) was the most common color developer with concentrations above 0.02 wt%, followed by BPA (36.0%), BPS (13.3%) and other BPS derivatives known as D8, D-90, BPS-MAE and TGSA, that are mainly present in adhesive labels. Sensitizers were determined in over 90% of the samples.

In vitro intestinal digestibility of cyclic aromatic polyester oligomers from polyethylene terephthalate (PET) and polybutylene terephthalate (PBT).

Linear and cyclic oligomers are unavoidable non-intentionally added substances (NIAS) present in food contact materials made from common polyesters such as polyethylene terephthalate (PET), polybutylene terephthalate (PBT) and polyester coatings. Although polyester oligomers can migrate into fats in significant amounts in high-temperature processes such as baking or frying, little is known about their toxicological properties and their behaviour in the human gastrointestinal tract. In the present study, first indications of a possible digestibility of polyester oligomers formed from the commonly used aromatic dicarboxylic acid terephthalic acid (TPA) are provided by in vitro experiments. Three cyclic polyester oligomers originated from PET (trimer) and PBT (dimer and trimer) were extracted from the raw materials, isolated and subjected to a simulated intestinal digestion. A fast cleavage (≥75% of the initial amount) of all three cyclic oligomers into their linear counterparts was detected already within the first hour of in vitro intestinal incubation. Subsequent hydrolysis to shorter chained linear oligomers was determined especially for the PET cyclic trimer. Degradation down to the monomer TPA was not observed. In terms of risk assessment and prioritisation for non-evaluated NIAS, the threshold of toxicological concern (TTC) concept is an appropriate tool. While cyclic polyester oligomers based on TPA are assigned to the TTC Cramer class III (high potential concern, exposure threshold 1.5 µg/kg body weight per day), the corresponding linear oligomers are expected to be of a lower probable toxicological concern (Cramer class I, 30 µg/kg body weight per day). A cleavage of cyclic polyester oligomers under human intestinal conditions, which was assessed to be likely by the provided in vitro experiments, could consequently affect the risk assessment on polyester oligomers.

Universal response quantification approach using a Corona Charged Aerosol Detector (CAD) - Application on linear and cyclic oligomers extractable from polycondensate plastics polyesters, polyamides and polyarylsulfones.

In terms of risk assessment especially for known and unknown substances migrating from food contact materials, quantification without corresponding reference substances currently poses a challenge. In the present study, the opportunity of a universal response quantification approach was evaluated by using a corona charged aerosol detector (CAD) for liquid chromatography combined with inverse gradient compensation. Characteristics of CAD detection in dependence of substance properties were analyzed with 46 randomly chosen reference substances. An almost equal CAD response (±20%) was achieved for non-volatile substances with a molecular weight of minimum 400 g/mol and a vapor pressure of maximum 10-8 Torr. We empirically defined an analytical parameter, Q50/35, the quotient of CAD peak areas at CAD evaporator temperatures of 50 °C and 35 °C, to predict the adequacy of the CAD universal response approach for quantification of known and unknown analyte substances. Exemplarily, we applied the CAD universal quantification approach for the determination of extractable oligomers below 1000 g/mol from a variety of food contact polycondensate plastic materials (e.g. polyesters like polyethylene terephthalate, polybutylene terephthalate, Tritan copolyester, polyamides 6, 6.6 and 6 T/6I and polyarylsulfones polyphenylsulfone and polyethersulfone). Quantitative results for in total 44 oligomers out of 11 materials were compared with established material-specific quantification methods using extracted oligomer mixtures as well as individual oligomers isolated from the mixtures. CAD-based quantification results were generally in accordance to published quantification approaches for polyamide oligomers and oligomers from polyarylsulfones. For oligomers extracted and isolated from polyester materials a slight underestimation was determined by CAD universal response approach. In terms of detection limits and accuracy, the universal CAD approach exhibits no advantages compared to established UV-methods, to date.

Polyphenylsulfone (PPSU) for baby bottles: a comprehensive assessment on polymer-related non-intentionally added substances (NIAS).

Polyphenylsulfone (PPSU) is a new material for the production of baby bottles. PPSU is a polyether plastic formally composed of bisphenol S (BPS) and 4,4'-dihydroxybiphenyl (DHBP), which both have slight endocrine activities in in vitro tests. So far, little is known about the presence and the release of potentially hazardous substances from PPSU baby bottles. In this study, we present a three-step approach for the analysis of PPSU starting with polymer characterisation in terms of chemical structure, total oligomer content and hydrolytic stability. Second is the determination of extractables focussing on monomers, monomer derivatives, linear and cyclic oligomers below 1000 Da and residual solvent. Third is a risk assessment on migration-related substances in accordance to European Union plastics regulation no. 10/2011 based on triplicate consecutive migration experiments using official milk simulant 50% ethanol. We analysed five types of PPSU baby bottles from different brands as well as corresponding raw materials from different manufacturers by various analytical techniques (high-performance liquid chromatography (HPLC)-diode array detector /fluorescence detector/Corona/electrospray ionisation-MS, HPLC-size exclusion chromatography, gas chromatography-mass spectrometry (GC-MS), 1H-NMR). We found significant variations of PPSU materials from different producers with regard to polymer and oligomer chain end groups (methoxylation, chlorination), while total oligomer content below 1000 Da was similar (mean about 0.48%). BPS was not detected above 0.3 mg/kg polymer in any PPSU sample. Residual DHBP content ranged between 1.7 and 15.5 mg/kg polymer. The most common oligomer in all PPSU samples was the cyclic tetramer (about 1200 mg/kg polymer), which is the only cyclic compound below 1000 Da. Residual solvent, sulfolane, was determined to a maximum of 1300 mg/kg polymer. In migration tests, we detected exceedances of neither specific migration limits for listed substances nor of thresholds of toxicological concern for non-listed substances (monomer derivatives, oligomers). Based on our analytical results, no concerns exist regarding migration of polymer-related substances from PPSU baby bottles.

Bisphenol A and alternatives in thermal paper receipts - a German market analysis from 2015 to 2017.

Bisphenol A (BPA) was commonly used as color developer for thermal paper such as cash register receipts, labels or tickets. Therefore, thermal paper was considered by the European Food Safety Authority (EFSA) as the main source of human exposure to BPA beside epoxy based food contact materials. In this study, a German market analysis on the use of BPA and alternative color developers in thermal paper receipts is provided for the years 2015, 2016 and 2017.114 (2015), 98 (2016) and 99 (2017) samples were randomly collected and analyzed by HPLC-DAD. In summary, BPA was still the most frequently found color developer (48.2% in 2015, 46.9% in 2016 and 52.5% in 2017). The most commonly used alternative was the phenol-free substance Pergafast® 201 (34.2%, 33.7%, 40.4%). The bisphenol analogs bisphenol S (BPS; 11.4%, 9.2%, 6.1%) and D8 (6.1%, 7.1%, 1.0%) were less common. Another phenol-free substituent, a urea urethane compound (UU), was also detected (3.1% in 2016). Concentrations of color developers in thermal paper ranged from 1.4 to 32.4 mg/g (median values between 2.5 and 15.9 mg/g). Concentrations of BPA were found to be highest followed by BPS, UU, Pergafast® 201 and D8. In addition, two pharmacologically active substances, dapsone (6.0 mg/g) and tolbutamide (5.5 mg/g), were detected in a non-marketed thermal paper, that was supposed to use ascorbic acid as initial color developer. Different release experiments of the detected color developers were performed. Sensitizers 1,2-diphenoxy-ethane, 1-phenylmethoxy-naphthalene and diphenylsulfone, used frequently in the thermal paper processes, were quantified.

Analysis of saturated and aromatic hydrocarbons migrating from a polyolefin-based hot-melt adhesive into food.

Hot-melt adhesives are widely utilised to glue cardboard boxes used as food packaging material. They have to comply with the requirements of Article 3 of the European Framework Regulation for food contact materials (1935/2004). The hot melt raw materials analysed mainly consisted of paraffinic waxes, hydrocarbon resins and polyolefins. The hydrocarbon resins, functioning as tackifiers, were the predominant source of hydrocarbons of sufficient volatility to migrate into dry foods: the 18 hydrocarbon resins analysed contained 8.2-118 g kg(-1) saturated and up to 59 g kg(-1) aromatic hydrocarbons eluted from GC between n-C16 and n-C24, substantially more than the paraffinic waxes and the polyolefins. These tackfier resins, especially the oligomers ≤ C24, have been characterised structurally by GC×GC-MS and (1)H-NMR spectroscopy. Migration into food was estimated using a simulating system with polenta as food simulant, which was verified by the analysis of a commercial risotto rice sample packed in a virgin fibre folding box sealed with a hot melt. About 0.5-1.5% of the potentially migrating substances (between n-C16 and n-C24) of a hot melt were found to be transferred into food under storage conditions, which can result in a food contamination in the order of 1 mg kg(-1) food (depending on the amount of potentially migrating substances from the hot melt, the hot melt surface, amount of food, contact time etc.). Migrates from hot melts are easily mistaken for mineral oil hydrocarbons from recycled cardboard.

Argentation high performance liquid chromatography on-line coupled to gas chromatography for the analysis of monounsaturated polyolefin oligomers in packaging materials and foods.

Multidimensional chromatography based on two-dimensional high performance liquid chromatography on-line coupled to gas chromatography (on-line HPLC-HPLC-GC) enables the separate analysis of saturated, monounsaturated and aromatic hydrocarbons in packaging materials like polyolefins or paperboard and their migrates into foods. Since normal-phase HPLC on silica gel did not preseparate saturated from monounsaturated hydrocarbons, a separation step on a normal-phase HPLC column treated in the laboratory with an optimized amount of silver nitrate was added. The preparation of this HPLC column and the instrumental set-up are described, followed by examples showing the potential of the method. In a preliminary investigation of 11 polyolefin granulates for food contact up to 40% monounsaturated hydrocarbons among the oligomers C16-35 were determined.

Suitability of tryptophan radiation products as markers for the detection of gamma-irradiated protein rich food.

During gamma-irradiation (5 kGy) of aqueous tryptophan (Trp) solutions small amounts of 5-, 6-, and 7-hydroxytryptophan (OH-Trp) (0.04-0.08 Mol-%) are formed. Protein rich food like shrimps contain reasonable amounts of non-protein bound Trp (100 mg/kg). In order to detect the treatment of shrimps with gamma-irradiation a method for the determination of OH-Trp in gamma-irradiated shrimps was developed. After homogenization, squeezing of shrimp samples and protein precipitation, a two-step-SPE-clean up was performed using a C18-cartridge and a propylsulfonic acid cation-exchange SPE followed by HPLC analysis with electrochemical detection (750 mV). Results showed that 5-OH-Trp contents in shrimp samples increased with applied doses up to 3 kGy and then decreased with higher doses. Other OH-Trp isomers were not detectable in the irradiated shrimps. Similarly no formation of 4-, 6-, and 7-OH-Trp was detected in model solutions containing the same amino acid composition as in shrimps. This indicates a suppression of the reaction of OH-radicals with Trp by the 300 fold molar excess of other amino acids acting as well as radical scavengers. Therefore, non-physiological OH-Trp isomers formed from free Trp are not suitable as markers for the detection of gamma-irradiated protein-rich foodstuff.

"Untypical aging off-flavor" in wine: synthesis of potential degradation compounds of indole-3-acetic acid and kynurenine and their evaluation as precursors of 2-aminoacetophenone.

Kynurenine (1) and indole-3-acetic acid (2) are considered as potential precursors of 2-aminoacetophenone (3), which is regarded to be the aroma impact compound causing an "untypical aging off-flavor" (UTA) in Vitis vinifera wines. The mechanism of the formation of 3 was studied using model fermentation and model sulfuration media spiked with 1 or 2 as potential precursors. Possible degradation products such as kynurenamine (4) and kynurenic acid (5), or skatole (6), 2-oxoskatole (7), 2-formamidoacetophenone (8), 2-oxindole-3-acetic acid (9), and 3-(2-formylaminophenyl)-3-oxopropionic acid (10) were evaluated by HPLC-UV of the fermentation and sulfuration media and comparison with synthesized 7, 8, 9, and 10. The synthesis of the possible precursor 4-(2-aminophenyl)-2,4-dioxobutanoic acid (11), a proposed metabolite of 1 failed because a spontaneous cyclization yields 5 and N-oxo-kynurenic acid (12), but not 11. It could be shown that the formation of 3 is triggered by an oxidative degradation of 2 after sulfuration with potassium bisulfite via the intermediates 10 and 8. However, no formation of 3 occurred during sulfuration of a model wine spiked with 1 or during fermentation of a model must spiked with 1 or 2.