1
|
Kubicova M, Eckardt M, Simat TJ. Migration of oligomers from Tritan™ copolyester: application of hydrolysis for overall oligomer determination. Food Addit Contam Part A Chem Anal Control Expo Risk Assess 2023; 40:1074-1095. [PMID: 37489979 DOI: 10.1080/19440049.2023.2232244] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2023] [Revised: 06/20/2023] [Accepted: 06/26/2023] [Indexed: 07/26/2023]
Abstract
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.
Collapse
Affiliation(s)
- Marie Kubicova
- Department of Food Chemistry and Food and Skin Contact Materials, Technische Universität Dresden, Dresden, Germany
| | - Martin Eckardt
- Department of Food Chemistry and Food and Skin Contact Materials, Technische Universität Dresden, Dresden, Germany
| | - Thomas J Simat
- Department of Food Chemistry and Food and Skin Contact Materials, Technische Universität Dresden, Dresden, Germany
| |
Collapse
|
2
|
Kubicova M, Eckardt M, Simat TJ. Oligomers in polybutylene terephthalate for food contact-strategies on identification, quantification, and risk assessment. Food Addit Contam Part A Chem Anal Control Expo Risk Assess 2022; 39:2002-2023. [PMID: 36206019 DOI: 10.1080/19440049.2022.2126531] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
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.
Collapse
Affiliation(s)
- Marie Kubicova
- Chair for Food Chemistry and Food and Skin Contact Materials, Technische Universität Dresden, Dresden, Germany
| | - Martin Eckardt
- Chair for Food Chemistry and Food and Skin Contact Materials, Technische Universität Dresden, Dresden, Germany
| | - Thomas J Simat
- Chair for Food Chemistry and Food and Skin Contact Materials, Technische Universität Dresden, Dresden, Germany
| |
Collapse
|
3
|
Characterization of Polyester Coatings Intended for Food Contact by Different Analytical Techniques and Migration Testing by LC-MS n. Polymers (Basel) 2022; 14:polym14030487. [PMID: 35160476 PMCID: PMC8839341 DOI: 10.3390/polym14030487] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2021] [Revised: 01/19/2022] [Accepted: 01/24/2022] [Indexed: 02/04/2023] Open
Abstract
Polymeric coating formulations may contain different components such as cross-linking agents, resins, lubricants, and solvents, among others. If the reaction process or curing conditions are not applied in a proper way, these components may remain unreacted in the polymeric network and could be released and migrate into foods. In this study, several polyester coatings intended for food contact were investigated. Firstly, Fourier-transform infrared spectroscopy with an attenuated total reflectance (ATR-FTIR) spectrometer and confocal Raman microscopy were used to identify the type of coating. Then, different techniques, including gas chromatography coupled to mass spectrometry (GC-MS) and analysis by matrix-assisted laser desorption coupled to time-of-flight mass spectrometry (MALDI-TOF-MS), among others, were used to investigate the potential volatile and non-volatile migrants. Moreover, migration assays were carried out to evaluate the presence of monomers and to tentatively identify possible oligomers below 1000 Da. The analyses were performed by liquid chromatography coupled to ion trap mass spectrometry (LC-MSn). Using the information collected from each analytical technique, it was possible to elucidate some of the starting substances used in the formulation of the polyester coatings analyzed in this study. In migration tests, several polyester oligomers were tentatively identified for which there is not toxicological data available and, therefore, no migration limits established to date.
Collapse
|
4
|
Alberto Lopes J, Tsochatzis ED, Karasek L, Hoekstra EJ, Emons H. Analysis of PBT and PET cyclic oligomers in extracts of coffee capsules and food simulants by a HPLC-UV/FLD method. Food Chem 2021; 345:128739. [PMID: 33333359 PMCID: PMC7896039 DOI: 10.1016/j.foodchem.2020.128739] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2020] [Revised: 10/12/2020] [Accepted: 11/23/2020] [Indexed: 12/27/2022]
Abstract
A HPLC-UV/FLD method was validated for the quantification of six polyethylene terephthalate (PET) and four polybutylene terephthalate (PBT) oligomers. PBT oligomers are EU regulated, while the PET ones are considered non-intentionally added substances (NIAS). LOQs were higher than 0.4 and 3.5 μg kg-1 for the simulants and in the polymer extracts, respectively. Recoveries ranged from 95 to 114 % with RSDs below 12%. Migration testing of PBT and polypropylene coffee capsules were performed with H2O and simulant C, and extracts were obtained with accelerated solvent extraction (ASE). For the latter legislative limits weren't surpassed. As no migration limits are existing for the analytes, both EFSA's toxicological threshold of concern (TTC) and sum of oligomers approaches were applied. The majority of oligomers were below the TTC (90 µg/person/day), but the limit value of 50 µg/kg food was surpassed for some capsules, which indicates a significant intake in both single and multiple consumption.
Collapse
Affiliation(s)
| | | | - Lubomir Karasek
- European Commission, Joint Research Centre (JRC), Geel, Belgium
| | - Eddo J Hoekstra
- European Commission, Joint Research Centre (JRC), Ispra, Italy
| | - Hendrik Emons
- European Commission, Joint Research Centre (JRC), Geel, Belgium
| |
Collapse
|
5
|
Brenz F, Linke S, Simat TJ. Linear and cyclic oligomers in PET, glycol-modified PET and Tritan™ used for food contact materials. Food Addit Contam Part A Chem Anal Control Expo Risk Assess 2020; 38:160-179. [DOI: 10.1080/19440049.2020.1828626] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Affiliation(s)
- Fabrian Brenz
- Chair of Food Science and Food Contact Materials, Department of Chemistry and Food Chemistry, TU Dresden, Dresden, Germany
| | - Susanne Linke
- Chair of Food Science and Food Contact Materials, Department of Chemistry and Food Chemistry, TU Dresden, Dresden, Germany
| | - Thomas J. Simat
- Chair of Food Science and Food Contact Materials, Department of Chemistry and Food Chemistry, TU Dresden, Dresden, Germany
| |
Collapse
|
6
|
Tsochatzis ED, Alberto Lopes J, Dehouck P, Robouch P, Hoekstra E. Proficiency test on the determination of polyethylene and polybutylene terephthalate cyclic oligomers in a food simulant. Food Packag Shelf Life 2020; 23:100441. [PMID: 32128312 PMCID: PMC6988440 DOI: 10.1016/j.fpsl.2019.100441] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2019] [Revised: 11/11/2019] [Accepted: 11/12/2019] [Indexed: 02/01/2023]
Abstract
Migration of food contact material substances. Mass fractions of PET and PBT cyclic dimers/trimers in food simulant D1. First proficiency test on polyester oligomers. Validation of analytical method. Assessment of analytical capabilities of EU NRLs and OCLs.
The outcome of a proficiency test (PT) organised by the European Union Reference Laboratory for Food Contact Materials (EURL-FCM) is presented. The PT was set up to assess the analytical performance of National Reference Laboratories (NRLs) and Official Control Laboratories (OCLs) in the determination of mass fractions of polyethylene terephthalate (PET) and polybutylene terephthalate (PBT) cyclic dimers and trimers in the official food simulant D1 containing ethanol and water (50:50 v/v). The EURL-FCM had developed and validated an analytical method based on HPLC-UV to monitor the homogeneity and stability of the target oligomers in the PT test items and to determine the respective assigned values, as prescribed in ISO 17043, 2010ISO 17043, 2010. The standard operating procedure of the method was provided to the participants and could be used instead of their own routine methods. Laboratory results were rated using z, z' and ζ scores in accordance with ISO 13528, 2015. The standard deviation for proficiency assessment, σpt, was set to 20 % of the respective assigned value, for all the four studied oligomers, based on the perception of experts. A total of 36 participants from 26 countries have registered to the exercise. They received two test items. Solution 1 consisted of food simulant D1 fortified with a known mass fraction of the four oligomers, while Solution 2 was obtained by a migration experiment with PET bottles and food simulant D1 and further fortification of the resulting solution with the four oligomers. The majority of the participating laboratories presented satisfactory results for the four PET and PBT oligomers. For the analysis of Solution 1, 79–88 % of the participants obtained |z (or z')-scores| below 2, while the satisfactory performances ranged from 71 to 85 % for Solution 2. This PT has been organised for the first time at EU level for the analysis of polyester oligomers and confirms that most of the NRLs are able to monitor properly these oligomers in the frame of Regulation (EU) No 10/2011.
Collapse
Affiliation(s)
- Emmanouil D Tsochatzis
- European Commission, Joint Research Centre, Via Enrico Fermi 2749, Ispra VA, 20127, Italy
| | - Joao Alberto Lopes
- European Commission, Joint Research Centre, Via Enrico Fermi 2749, Ispra VA, 20127, Italy
| | - Pieter Dehouck
- European Commission, Joint Research Centre, Via Enrico Fermi 2749, Ispra VA, 20127, Italy
| | - Piotr Robouch
- European Commission, Joint Research Centre, Via Enrico Fermi 2749, Ispra VA, 20127, Italy
| | - Eddo Hoekstra
- European Commission, Joint Research Centre, Via Enrico Fermi 2749, Ispra VA, 20127, Italy
| |
Collapse
|
7
|
Tsochatzis ED, Alberto Lopes J, Holland MV, Reniero F, Emons H, Guillou C. Isolation, Characterization and Structural Elucidation of Polybutylene Terephthalate Cyclic Oligomers and Purity Assessment Using a ¹H qNMR Method. Polymers (Basel) 2019; 11:polym11030464. [PMID: 30960448 PMCID: PMC6473883 DOI: 10.3390/polym11030464] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2019] [Revised: 02/27/2019] [Accepted: 03/05/2019] [Indexed: 12/11/2022] Open
Abstract
The use of polybutylene terephthalate (PBT) as a food contact material is increasing over the last years. Typical contaminations in the final PBT product include its cyclic oligomers, which are allowed as additives in food contact plastics according to Regulation (EU) No. 10/2011. Their investigation is currently limited by the lack of analytical standards and physical-chemical information. Therefore, four PBT cyclic oligomers have been isolated and purified from a PBT raw material with an automated preparative HPLC-DAD system. Comprehensive characterization of the compounds was performed using Ultra-High Performance Liquid Chromatography (UHPLC) with high resolution time-of-flight mass spectrometry, Fourier-Transform Infrared spectroscopy (FTIR), Differential Scanning Calorimetry (DSC) and Nuclear Magnetic Resonance (NMR) spectroscopy. The purity of each oligomer was assessed using a 1H qNMR method and ranged from 96.1% to 97.0% for PBT tetramer and trimer respectively. The availability of pure and well characterized PBT cyclic oligomer standards will facilitate future studies of release from plastic food packaging materials.
Collapse
Affiliation(s)
- Emmanouil D Tsochatzis
- European Commission, Joint Research Centre (JRC), Via Enrico Fermi 2749, I-20127 Ispra (VA), Italy.
| | - Joao Alberto Lopes
- European Commission, Joint Research Centre (JRC), Via Enrico Fermi 2749, I-20127 Ispra (VA), Italy.
| | - Margaret V Holland
- European Commission, Joint Research Centre (JRC), Via Enrico Fermi 2749, I-20127 Ispra (VA), Italy.
| | - Fabiano Reniero
- European Commission, Joint Research Centre (JRC), Via Enrico Fermi 2749, I-20127 Ispra (VA), Italy.
| | - Hendrik Emons
- European Commission, Joint Research Centre (JRC), Via Enrico Fermi 2749, I-20127 Ispra (VA), Italy.
| | - Claude Guillou
- European Commission, Joint Research Centre (JRC), Via Enrico Fermi 2749, I-20127 Ispra (VA), Italy.
| |
Collapse
|
8
|
Brenz F, Linke S, Simat T. Linear and cyclic oligomers in polybutylene terephthalate for food contact materials. Food Addit Contam Part A Chem Anal Control Expo Risk Assess 2017; 35:583-598. [DOI: 10.1080/19440049.2017.1414958] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Affiliation(s)
- Fabrian Brenz
- Department of Chemistry and Food Chemistry, Chair of Food Science and Food Contact Materials, Technical University of Dresden, Dresden, Germany
| | - Susanne Linke
- Department of Chemistry and Food Chemistry, Chair of Food Science and Food Contact Materials, Technical University of Dresden, Dresden, Germany
| | - Thomas Simat
- Department of Chemistry and Food Chemistry, Chair of Food Science and Food Contact Materials, Technical University of Dresden, Dresden, Germany
| |
Collapse
|