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)

Talanta 266 (2024) 124999 Available online 28 July 2023 0039-9140/© 2023 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/). 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 (UPLCIMS-QTOF) Paula Vera a , Elena Canellas a , Nicola Dreolin b , Jeff Goshawk b , Cristina Nerín a , * a Analytical Chemistry Department, GUIA Group, I3A, EINA, University of Zaragoza, M a de Luna 3, 50018, Zaragoza, Spain b Waters Corporation, Wilmslow, SK9 4AX, United Kingdom ARTICLE INFO Keywords: Chemical migration PFAS Food packaging Ion mobility Tenax ABSTRACT 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 μ g/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. 1. Introduction Per-polyfluoroalkyl substances (PFAS) refer to a group of synthetic fluorine compounds with distinctive chemical and physical properties, such as resistance to temperature and chemicals, repellency to oil and water, and surfactant characteristics. These substances have been extensively utilized in various industrial applications, including firefighting foams, carpeting, cleaners, cosmetics, paints, adhesives, insecticides, clothing, metal plating and food contact materials (FCMs). PFAS are widely produced and used, and their chemical and thermal stability causes them to persist in the environment. As a result, PFAS have been found to contaminate soil and water, and the bioaccumulation of these compounds in animals and humans has been detected [1–3]. Other persistent compounds in nature that have presented challenges for environmental chemists include ultrafine silico-manganese fumes (SMF), a waste produced during steel production that has been encapsulated in alginate and lyophilized to form cryogenic SMF beads [4]; heavy metals adsorbed by synthesized fungi biosorbents [5], or Pb (II) metal adsorbed by sesame oil cake (SOC), a waste product from the oil industry [6]; and cationic dyes such as methylene blue (MB) and celestine blue (CB) adsorbed by a nano-composite of montmorillonite [7] or a nanocomposite of carbon nanotubes [8] for removal from aqueous environments. PFAS-contaminated food is a primary source of human exposure, which occurs through direct or indirect contact with PFAS-coated surfaces. In Europe, concentrations of PFAS in individuals have been found to exceed EFSA’s proposed safety threshold [9]. PFAS are present in a variety of FCMs that we use in our everyday * Corresponding author. E-mail addresses: [email protected] (P. Vera), [email protected] (E. Canellas), [email protected] (N. Dreolin), [email protected] (J. Goshawk), [email protected] (C. Nerín). Contents lists available at ScienceDirect Talanta journal homepage: www.elsevier.com/locate/talanta https://doi.org/10.1016/j.talanta.2023.124999 Received 17 December 2022; Received in revised form 6 July 2023; Accepted 25 July 2023 Talanta 266 (2024) 124999 2 lives. These FCMs include surfactants found in Polytetrafluoroethylene (PTFE) materials used to manufacture kitchen utensils and to create nonstick coatings, which make it easier to clean the surfaces of pots and pans. Furthermore, PFAS can be added to packaging materials for processed foods, such as pizza boxes, potato packets and wrapping paper, to act as water repellents and oleophobic coatings that prevent fats and water from the food from transferring to the paper or cardboard packaging [10]. At the Stockholm Convention in 2020, it was agreed that the use of PFAS should be restricted as much as possible to protect human health and the environment. The recent EU Regulation (EU) 2020/784 [11] restricted the use of PFOA, its salts and PFOA related compounds [12]. This regulation sets a maximum concentration of 0.025 mg/kg for PFOA and its salts, and a maximum concentration of 1 mg/kg for PFOA-related compounds or a combination of those compounds. In addition, Commission Recommendation (EU) 2019/794 [13] recommends the investigation of the presence of PFAS in FCM, specifically its presence in paper and board-based materials. A range of PFAS compounds have been studied in different matrices including water, foods, air and FCMs. These studies were carried out using either non-specific methods to determine the total amount of fluorine in samples [14], or a specific method such as liquid chromatography (LC or UHPLC) coupled to a triple quadrupole mass spectrometer (TQ-MS), being a powerful analytical tool for quantitative analysis from the point of view of accuracy and precision, or a quadrupole time-of-flight mass spectrometer (QTOF-MS) [15–18]. QTOF-MS offers high mass resolution analysis, which allows for greater accuracy in differentiating ions with similar mass-to-charge (m/z) ratios. It also provides highly accurate mass measurements, allowing better identification of unknown compounds through database searches. Additionally QTOF-MS generates information-rich data in a single analysis, simultaneously generating both precursor and product ion spectra. This capability enables the detection and identification of a diverse range of compounds in a single run of complex samples. Moreover, QTOF-MS boasts a wider dynamic range than triple quadrupole, which enables it to detect and quantify a broader range of analytes at different concentrations. In contrast, TQ-MS usually provides unit mass fragments instead of high resolution MS, but the sensitivity, working with collision cell, is higher than that of QTOF-MS. Ultrahigh performance liquid chromatography (UPLC) coupled to an ion-mobility quadrupole time-of-flight mass spectrometer (IM-QTOFMS) is a relatively new technique and probably one of the most powerful analytical technologies for the determination and characterization of non-volatile compounds. The incorporation of travelling wave ion mobility (TWIMS) provides an additional dimension of separation. Ions introduced to the TWIMS device are separated in the ion-mobility drift region via a combination of their size, shape and charge. Precursor and fragment ions can subsequently be aligned using both retention time and drift time which results in cleaner, less complex spectra, with reduced noise and provides the potential of achieving lower limits of detection. IMS also enables the determination of collision cross section (CCS) values, which are strongly related to the size, charge and shape of the ions. As such, this technique yields a higher confidence in the identification of compounds by combining CCS with accurate mass, retention time, fragmentation pattern and isotopic distribution. The primary advantage of incorporating IMS into MS is its ability to separate isomers with similar mass-to-charge ratios but differing shapes or sizes. This is achieved through the measurement of the ion’s collision cross-section (CCS), which is indicative of its size and shape. By using IMS, the accuracy of isomer identification can be improved and false positive rates can be reduced. This additional dimension of separation enhances specificity in omics studies, making it a critical technique in this field. It has been employed in recent studies to detect compounds that have migrated from various FCMs [19–27]. However, no such study has been conducted to determine the extent of PFAS migration from FCMs, with only few articles found on the analysis of PFAS in environmental water and human serum samples [28–32]. This study aimed to identify the migration levels of various PFAS families from Food Contact Materials (FCMs) made from water repellent and oleophobic coated materials, including cardboard, paper, biodegradable materials and Teflon. 2. Materials and methods 2.1. Reagents Perfluorocarboxylic acid substances (PFCAs): Perfluorobutanoic Acid, Perfluorohexanoic Acid, Perfluorooctanoic Acid, Perfluorodecanoic Acid, Perfluorododecanoic Acid, perfluorotetradecanoic acid. Perfluorosulfonic acid substances (PFSAs): Perfluorobutanesulfonic acid, Perfluorohexanesulfonic Acid, Perfluorooctanesulfonic Acid. Perfluorooctanesulfonamidoacetic acid substances (FOSAAs): N -methyl perfluorooctane sulfonamidoacetic acid, N-ethyl perfluorooctane sulfonamidoacetic acid. Perfluorotelomer sulfonates (FTSs): Sodium 1H,1H,2H,2H perfluoro1,1-hexanesulfonate, sodium 1H,1H,2H,2H perfluoro-1,1decanesulfonate and sodium perfluoro-1-pentanesulfonate [penta-sulfate] were purchased from Sigma-Aldrich, Química SA (Spain). High purity ethanol, water, methanol and acetonitrile for HPLC were purchased from Scharlau Chemie S.A (Spain). Tenax® and Ammonium Acetate were supplied by Supelco (Bellefonte, PA). Individual standard solutions of 1000 μ g/g were prepared in ethanol by weighing 0.01 g of each compound in 20 mL vial of capacity. Approximately 18 g of ethanol was added to dissolve them. The resulting solutions were then diluted further to a concentration of 10 μ g/g. Subsequently, a stock solution containing a mixture of 14 certified standards was prepared at 1 μ g/g and serial dilutions were prepared using ethanol. 2.2. Samples collection A range of food contact materials, with an emphasis on those for baked products, were studied. In general, the basic criterion for the collection of real samples was designed to ensure that the samples were from different supermarkets, of different materials and also that they were representative and differentiated from two regions such as Spain and China. All of the samples were water repellent and oleophobic coated and were made from cardboard, paper, recycled cardboard, biodegradable sugar cane and starch and Teflon. All but one of the samples were trays principally used as substrates for either hot pastries, such as croissants, slices pizza, bakery products and hot dogs, or for sushi. One sample was a Teflon coated fabric used to wrap or heat sandwiches directly in the pan. Additional information on Table 1 Samples of paper, cardboard and Teflon studied. Code Description Material Origin Tray 1 Tray for croissants or slices pizza Cardboard Spain Tray 2 Tray for croissants or slices pizza Recycled cardboard Spain Tray 3 Tray for bakery Compact paper Spain Tray 4 Tray for hot dogs Recycled cardboard Spain Tray 5 Tray for bakery Biodegradable material made of sugar cane Spain Tray 6 Tray for sushi Cardboard Spain Tray 7 Tray for bakery Cardboard China Tray 8 Tray for slices pizza Cardboard China Tray 9 Tray for bakery Recycled cardboard China Tray 10 Tray for bakery Biodegradable starch material China Tray 11 Tray for sushi Cardboard China Tray 12 Tray for sushi Recycled cardboard China Coating Coating of Teflon used to wrap or heat sandwiches directly in the pan Cardboard Spain P. Vera et al. Talanta 266 (2024) 124999 3 the samples is provided in Table 1. It was anticipated that all materials could contain PFAS compounds added to their formulation to avoid the transfer of fats and water from the food to the packaging material. 2.3. UPLC-IMSQTOF analysis An ACQUITY UPLC® I-Class system coupled to a Vion IMS QTOF mass spectrometer with electrospray ionization (Waters, Wilmslow, UK) was used to analyze the samples. A UPLC BEH C18 column (1.7 μ m particle size, 2.1 mm ×100 mm) was used with a flow rate of 0.3 mL/ min at 35 ◦C [33]. ACQUITY UPLC® I-Class system is equipped with a binary solvent manager pump that delivers precise and accurate gradients for optimal chromatographic separations. The mobile phase and the gradient were optimized as follows: solvent A: water/acetonitrile 90:10 (v/v) with 20 mM ammonium acetate, solvent B: methanol/acetonitrile 60:40 (v/v). The gradient was A: 85%/ B: 15% (0min), A: 65%/B: 35% (2min), A: 45%/B: 55% (4min), A: 25%/ B: 75% (6min), A: 5%/B: 95% (8min), A: 85%/B: 15% (10min). The injection volume was 10 μ L. The Vion IMS QTOF was operated in ESIion (sensitivity mode), with a capillary voltage of 1 kV and a cone voltage of 30 V. The source and desolvation temperatures were set to 120 ◦C and 500 ◦C, respectively, while nitrogen was used as desolvation gas with a flow rate of 800 L/h. The LockSpray, containing Leucine-Enkephalin ([M −H]- adduct, m/z 554.2620) at a concentration of 100 ng/mL, was infused at a rate of 15 μ L/min to enable real time mass correction. Argon was used as the collision gas and nitrogen was used as the ion-mobility gas. IMS gas flow rate was 25 mL/min, wave velocity 250 m/s, IMS pulse height 45 V. Mass and CCS calibration was performed using Major Mix kit (Waters Corp.) The data were acquired in high definition MS E (HDMS E ) mode and both data acquisition and processing were performed using the UNIFI v1.9 Scientific Information System (Waters, Wilmslow, UK). 2.4. Migration assays The migration tests were carried out using Tenax® as a food simulant for two main reasons. Firstly, most of the packaging samples were cardboard or paper trays and Tenax is used as solid simulant, mimicking the characteristics of dried foods, and therefore representative of the foods exposed to this type of material. Secondly, the intended use of the samples is for the preservation or preparation of cereal products, pastries, cakes and other baking products and Tenax is appropriate for the simulate these food classes as stated in REGULATION (EU) Nº 10/2011 [34]. Some of the food products that may be exposed to the packaging samples could be represented by a food simulant for high fats content, food simulant D (95% ethanol), for example. However, it was found that this simulant partially dissolved the samples so it was not possible to prepare a complementary assay due to the incompatibility between the samples and the simulant. 2.4.1. Sample preparation and extraction procedure Prior to migration analysis, the optimal number of extractions needed to achieve the highest compound recoveries from Tenax simulant was determined. 0.32 g of Tenax samples were spiked with 100 μ L of a standard solution containing the 12 PFAS at a concentration of 1 μ g/g. Two experiments were subsequently developed. In the first experiment, two consecutive extractions were carried out in an ultrasonic bath, each lasting an hour, using 3 mL of ethanol. The extracts were combined and subsequently concentrated to 0.5 mL under a nitrogen stream. In the second experiment, three consecutive extractions were performed, each lasting an hour, using 3 mL of ethanol. Again,the extracts were combined and concentrated to 0.5 mL [35]. Three repetitions of each experiment were carried out to ensure accuracy. The percentage of recovery was calculated for each compound in both experiments by analyzing the samples using UPLC-IMS-QTOF analysis, as previously described. The areas obtained from each compound spiked after two and three extractions were divided by the areas obtained after injection of the same compound at a concentration of 0.2 μ g/g (taking into account 100 μ L of a standard solution spiked at a concentration of 1 μ g/g and a final volume of 0.5 mL after concentration). 2.4.2. Migration assays and risk assessment To avoid false positive results and contaminated blanks, the Tenax used as a simulant was cleaned with ethanol in a Soxhlet for 8 h and dried. Each food packaging sample was cut into 2 ×4 cm pieces, and 0.32 g of Tenax was spread evenly on the inner surface of each sample, following the UNE-EN 14338 standard of 4 g Tenax/dm 2 [36]. The samples were then placed on Petri plates and kept in an oven set at 40 ◦C for 3 days to simulate challenging usage conditions (20 ◦C <T ≤40 ◦C, 1 day <t ≤3 days) [34]. The Teflon-coated samples, which are used to heat sandwiches directly in a pan, were subjected to additional conditions of 175 ◦C for 5 min, which is the most challenging condition of their use (t ≤5 min and 150 ◦C <T <175 ◦C). Three replicates of each sample and a blank were prepared. After the migration assays were completed, the samples were extracted and analyzed by UPLC-IMS-QTOF, with calibration curves prepared using standard solutions in ethanol for quantitation. Migration values were calculated by determining the absolute mass migrating in mg and dividing it by 0.08 dm 2 to account for the sample size. The factor of 6 dm 2 of simulant per kg was also taken into account according to EU regulation [34]. The migration levels of each compound were compared to the maximum concentrations set by EU regulation (EU 2020/784) [11], which is 0.025 mg/kg for PFOA and its salts, and 1 mg/kg for PFOA-related compounds or a combination of those compounds. 3. Results and discussion 3.1. Determination of PFAS using UPLC-IMS-QTOF This technique resulted in cleaner and less complex spectra by aligning precursors and fragment ions based on both retention time and drift time. Furthermore, in addition to providing accurate m/z values of precursor and fragmentation ions, ion-mobility mass spectrometry allowed for the determination of a Collision Cross Section (CCS) value, which indicated the size and shape of each molecule. The chromatogram of the investigated compounds analyzed by UPLC-IMS-QTOF was shown in Fig. 1. The PFAS studied can be grouped into families as shown in Table 2 in which retention times, precursor and fragment ions and CCS values are also reported. CCS values were calculated as the average of all CCS values obtained for each compound at all seven calibration points analyzed in triplicate. All compounds were detected in ESI-, appearing either as deprotonated adducts, or [M −Na] - adducts in the case of FTSs and PFPeS. For PFCAs, the most abundant ions observed in the low energy spectrum were the [M −H] - and the [2M −H] - adducts. In the high energy spectrum, the most abundant fragment observed was the loss of 43.9897 (CO 2 ) and several other common fragments, such as m/z values 118.9925, 168.9805, 218.9861, corresponding to C 2 F 5 , C 3 F 7 and C 4 F 9 respectively, were detected. Fig. 2a provides an example of the mass spectra for perfluorooctanoic acid compounds. The CCS values for this class of compounds generally increased with the length of the perfluorocarboxylic chain, except for perfluorododecanoic acid and perfluorotetradecanoic acid, for which the CCS values were lower than those of compounds with shorter chain lengths. One major difference noted between PFCAs and PFSAs was the low intensity or absence of the [2M −H] - ion in the low-energy spectrum for latter compound class PFSAs. Moreover, the intensities of the product ions for PFSAs were lower in the high-energy spectra compared to those P. Vera et al. Talanta 266 (2024) 124999 4 Fig. 1. Chromatogram of the investigated compounds analyzed by UPLC-IMS-QTOF at the top and the extracted ion chromatogram of the PFBS compound at the bottom. Table 2 Compounds analyzed by UPLC-IMS-QTOF, with their retention times (RT), ion detected, precursor and fragment ions and collision cross section (CCS). Name Acronym RT (min) Ion detected Precursor ion (m/z) Fragment ion 1 (m/z) Fragment ion 2 (m/z) Fragment ion 3 (m/z) CSS (Å 2 ) Perfluorocarboxylic acid substances (PFCAs) Perfluorobutanoic Acid PFBA 1.96 [M −H] 212.9787 168.9890 167.3 ± 0.1 Perfluorohexanoic Acid PFHxA 4.05 [M −H] 312.9725 268.9825 118.9921 198.8 ± 0.4 Perfluorooctanoic Acid PFOA 5.49 [M −H] 412.9666 368.9769 168.9892 218.9861 229.7 ± 0.2 Perfluorodecanoic Acid PFDA 6.53 [M −H] 512.9606 468.9708 218.9861 268.9829 259.1 ± 0.5 Perfluorododecanoic Acid PFDoA 7.36 [M −H] 612.9558 568.9646 168.9892 218.9861 190.5 ± 0.7 Perfluorotetradecanoic Acid PFTeDA 8.21 [M −H] 712.9486 668.9592 168.9892 218.9859 208.9 ± 0.9 Perfluorosulfonic acid substances (PFSAs) Perfluorobutanesulfonic acid PFBS 3.68 [M −H] 298.9435 168.9896 118.9927 218.9868 129.6 ± 0.1 Perfluorohexanesulfonic acid PFHxS 5.12 [M −H] 398.9371 168.9893 229.9479 279.9435 146.3 ± 0.9 Perfluorooctanesulfonic acid PFOS 6.26 [M −H] 498.9312 168.9892 118.9927 279.9446 163.6 ± 0.3 Perfluorooctanesulfonamidoacetic acids substances (FOSAAs) N -methyl perfluorooctane sulfonamidoacetic acid NMeFOSAA 6.72 [M −H] 569.9676 418.9732 218.9858 511.9619 189.1 ± 0.6 N-ethyl perfluorooctane sulfonamidoacetic acid N-EtFOSAA 6.93 [M −H] 583.9827 525.9777 265.1508 168.9889 192.7 ± 0.7 Fluorotelomer sulfonates substances (FTSs) Sodium 1H,1H,2H,2H perfluoro-1,1hexanesulfonate 4:2 FTS 3.83 [M −Na] 326.9640 306.9672 286.9619 202.9932 146.9 ± 0.3 Sodium 1H,1H,2H,2H perfluoro-1,1decanesulfonate 8:2 FTS 6.44 [M −Na] 526.9619 506.9556 486.9495 392.9767 181.9 ± 0.1 Perfluoroalkanesulfonates substances (PFASs) Sodium perfluoro-1-pentanesulfonate PFPeS 4.50 [M −Na] 348.9394 168.9885 229.9477 341.1974 137.8 ± 0.1 The precursor ions (m/z) highlighted were used to determine the CCS value. P. Vera et al. Talanta 266 (2024) 124999 5 of PFCAs. Some common product ions observed for PFCAs at lower intensities were 129.9598, 229.9479 and 279.9446 m/z (CF 2 O 3 S, C 3 F 6 O 3 S and C 4 F 8 O 3 S, respectively) which were associated with the fragmentation of the sulfur-containing chain. An illustration of the low and high energy mass spectra for perfluorooctanesulfonic acid is given in Fig. 2b. The family of compounds known as perfluorooctanesulfonamidoacetic acids could be identified by the presence of strong fragments, with the loss of 58.0057 (C2H2O2) being the most prevalent. Additionally, common fragments with m/z values of 118.9925, 168.9805 and 218.9861 were also detected. An example of the mass spectra for the compound N-methyl perfluorooctane sulfonamidoacetic acid can be seen in Fig. 2c. Finally, the FTSs and PFPeS families had distinct characteristics compared to other compound classes, as they exhibited the loss of Na. The fluorotelomer sulfonate substances family shared a common fragment ion resulting from the loss of 20.0065 (HF). However, for sodium perfluoro-1-pentanesulfonate, only minimal fragments were detected. An example of the mass spectra for Sodium 1H,1H,2H,2H perfluoro-1,1hexanesulfonate is shown in Fig. 2d. Fig. 2. a. The high-energy spectrum of perfluorooctanoic acid with the corresponding low-energy spectrum inset to the right. b. The high-energy spectrum of perfluorooctanesulfonic acid with the corresponding low-energy spectrum inset to the right. c. The high-energy spectrum of N -methyl perfluorooctane sulfonamidoacetic acid with the corresponding low-energy spectrum inset to the right. d. The high-energy spectrum of sodium 1H,1H,2H,2H perfluoro-1,1-hexanesulfonate with the corresponding low-energy spectrum inset to the right. P. Vera et al. Talanta 266 (2024) 124999 6 3.2. Migration results Prior to performing the migration assays, the number of extractions for each compound from Tenax was optimized by spiking Tenax with the certified standards and the recoveries, quantitation parameters and limits of detection (LOD) and quantification (LOQ) obtained from this process are shown in Table 3. The values of LOD and LOQ were determined by considering the minimum amount of the analyte of interest that produces a chromatographic peak with a signal-to-noise (S/N) ratio of 3:1 and 10:1, respectively, in the presence of background signal noise [37]. Higher recoveries were obtained on using three consecutive extractions ranging between 77.5 ±5.4% for 4:2 FTS and 119 ±22% for PFBS. Very low limit of detections (ranging between 0.07 and 3.42 μ g/kg) and good linearity (R 2 >0.99) were obtained. Validation tests provided good results of these tested parameters. The sensitivity of the method was Fig. 2. (continued). P. Vera et al. Talanta 266 (2024) 124999 7 mostly comparable to other methods based on UPLC-QTOF and UPLCMS/MS as ythey provided lower values of detection limits due to its spectral cleaning capability [38–43]. The migration results are shown in Table 4. The migration of PFAS from most of the samples obtained from a local Spanish market (trays 1–6) was lower than the LODs of the method. However, for tray 2 and tray 4, which were made of recycled cardboard [44], the migration values of PFOA and PFOS were above the LOD. For tray 2 the levels of migration of PFOA and PFOS were found to be below their limit of quantifications (LOQs), at <2.58 μ g/kg and <1.39 μ g/kg, respectively. For tray 4 the levels of migration of PFOA and PFOS were found to be 3.15 ±0.02 μ g/kg and 2.22 ±0.02 μ g/kg, respectively. The levels of migration of PFAS from the samples obtained from a Chinese market (trays 7–12) were significantly elevated compared to the migration levels from the samples from the Spanish market. The only trays for which the level of migration of PFAS were below the LOD were trays 7 and 10. In the other samples from the Chinese market, the migration level of compounds belonging to the PFCA and PFSA classes were found to range between 1.55 and 22.3 μ g/kg, with the highest concentrations determined for PFOA. It is worth noting that the level of migration of the compounds in these families decreased with the increasing length of the fluorinated chain [14]. Furthermore, Table 3 Calibration parameters, coefficient of correlation (R 2 ), limit of detection (LOD), limit of quantification (LOQ) and extraction recoveries (%) for the compounds analyzed. Compounds Acronym Calibration equation R 2 LOD ( μ g/ kg) LOQ ( μ g/ kg) Linear range ( μ g/ kg) Recoveries (%) 2 extractions Recoveries (%) 3 extractions Perfluorobutanoic Acid PFBA y =13.8x-80.7 0.9955 3.42 11.4 11.4–488 74.1 ±2.2 80.7 ±4.0 Perfluorohexanoic Acid PFHxA y =161x-4064 0.9991 1.98 6.60 6.30–1070 79.3 ±2.9 90.4 ±6.1 Perfluorooctanoic Acid PFOA y =401x+189 0.9950 0.89 2.58 2.98–1100 79.7 ±5.6 89.0 ±7.9 Perfluorodecanoic Acid PFDA y =137x+3656 0.9934 0.44 1.47 1.47–1180 73.5 ±2.9 83.7 ±2.5 Perfluorododecanoic Acid PFDoA y =325x+1825 0.9971 0.42 1.40 1.40–1130 99.1 ±5.9 105 ±12 Perfluorotetradecanoic Acid PFTeDA y =335x-4610 0.9951 0.40 1.33 1.34–1181 74.6 ±4.4 92.6 ±6.5 Perfluorobutanesulfonic acid PFBS y =9597x+5885 0.9978 0.40 1.33 1.33–26 84.7 ±7.0 119 ±22 Perfluorohexanesulfonic acid PFHxS y =3415x+14321 0.9991 0.38 1.27 1.27–505 105 ±16 104 ±10 Perfluorooctanesulfonic acid PFOS y =4161x+265 0.9991 0.41 1.39 1.39–110 81.5 ±4.9 118 ±11 N -methyl perfluorooctane sulfonamidoacetic acid NMeFOSAA y =3163x+6722 0.9959 0.06 0.20 0.19–400 54.1 ±3.5 89.5 ±3.5 N-ethyl perfluorooctane sulfonamidoacetic acid N-EtFOSAA y =266x+3533 0.9963 0.07 0.23 0.25–1020 95 ±7.6 103 ±8.2 Sodium 1H,1H,2H,2H perfluoro-1,1hexanesulfonate 4:2 FTS y =939x+4550 0.9963 0.37 1.23 1.23–250 65.5 ±1.5 77.5 ±5.4 Sodium 1H,1H,2H,2H perfluoro-1,1decanesulfonate 8:2 FTS y =4751x+1645 0.9964 0.07 0.23 0.24–43 69.4 ±4.1 99.3 ±5.1 Sodium perfluoro-1-pentanesulfonate PFPeS y =12279x+1813 0.9928 0.08 0.26 0.25–45 72.7 ±11 103 ±5.2 LOD: Limit of detection and LOQ: Limit of quantification. Table 4 Migration results to Tenax expressed as: μ g of compound/kg of simulant. Samples/ Compounds Tray 1 Tray 2 Tray 3 Tray 4 Tray 5 Tray 6 Tray 7 Tray 8 Tray 9 Tray 10 Tray 11 Tray 12 Coating T =40 ◦C Coating T = 175 ◦C PFBA <3.42 <3.42 <3.42 <3.42 <3.42 <3.42 <3.42 12.5 ± 1.0 16.3 ± 0.32 <3.42 <11.4 13.5 ± 1.1 <3.42 <3.42 PFHxA <1.98 <1.98 <1.98 <1.98 <1.98 <1.98 <1.98 8.71 ± 0.43 11.9 ± 1.0 <1.98 <6.3 8.92 ± 0.80 <1.98 <1.98 PFOA <0.89 <2.58 <0.89 3.15 ± 0.02 <0.89 <0.89 <0.89 9.58 ± 0.61 18.5 ± 0.9 <0.89 5.33 ± 0.21 22.3 ± 1.9 2.61 ± 0.34 4.12 ± 0.20 PFDA <0.44 <0.44 <0.44 <0.44 <0.44 <0.44 <0.44 5.33 ± 0.47 7.55 ± 0.6 <0.44 <0.44 7.33 ± 0.58 <0.44 <0.44 PFDoA <0.42 <0.42 <0.42 <0.42 <0.42 <0.42 <0.42 2.11 ± 0.10 4.23 ± 0.29 <0.42 <0.42 4.14 ± 0.37 <0.42 <0.42 PFTeDA <0.40 <0.40 <0.40 <0.40 <0.40 <0.40 <0.40 <0.40 1.83 ± 0.09 <0.40 <0.40 2.12 ± 0.06 <0.40 <0.40 PFBS <0.40 <0.40 <0.40 <0.40 <0.40 <0.40 <0.40 5.24 ± 0.41 3.18 ± 0.22 <0.40 <1.33 6.99 ± 0.35 <0.40 <0.40 PFHxS <0.38 <0.38 <0.38 <0.38 <0.38 <0.38 <0.38 2.15 ± 0.19 1.55 ± 0.12 <0.38 <0.38 9.2 ± 0.6 <0.38 <0.38 PFOS <0.41 <1.39 <0.41 2.22 ± 0.02 <0.41 <0.41 <0.41 7.33 ± 0.51 8.57 ± 0.77 <0.41 2.17 ± 0.10 15.3 ± 1.4 <0.41 <0.41 N-MeFOSAA <0.06 <0.06 <0.06 <0.06 <0.06 <0.06 <0.06 <0.06 3.15 ± 0.28 <0.06 <0.06 2.15 ± 0.14 <0.06 <0.06 N-EtFOSAA <0.07 <0.07 <0.07 <0.07 <0.07 <0.07 <0.07 <0.07 1.22 ± 0.06 <0.07 <0.07 0.86 ± 0.02 <0.07 <0.07 4:2 FTS <0.37 <0.37 <0.37 <0.37 <0.37 <0.37 <0.37 <0.37 <0.37 <0.37 <0.37 <0.37 <0.37 <0.37 8:2 FTS <0.07 <0.07 <0.07 <0.07 <0.07 <0.07 <0.07 <0.07 <0.07 <0.07 <0.07 <0.07 <0.07 <0.07 PFPeS <0.08 <0.08 <0.08 <0.08 <0.08 <0.08 <0.08 <0.08 <0.08 <0.08 <0.08 <0.08 <0.08 <0.08 P. Vera et al. Talanta 266 (2024) 124999 8 compounds belonging to the FOSAA family (N-EtFOSAA and N-MeFOSAA) were detected at concentrations ranging from 0.86 to 3.15 μ g/kg for trays 9 and 12. It is worth noting that no fluorotelomer sulfonates substances (FTS) and perfluoroalkanesulfonates substances (PFAS) were detected above the LOD in any of the tray samples. Only PFOA was found to migrate above the LOD from the Teflon-coated sample. The level of migration was found to increase with temperature even though the contact time at the higher temperature is significantly lower than that at the lower temperature [12]. This phenomenon can be explained by the concept of diffusion, which is the process where molecules move from areas of high concentration to areas of low concentration. Diffusion is driven by the kinetic energy of the molecules and is affected by various factors, including temperature. With an increase in temperature, the kinetic energy of molecules also increases, resulting in a higher diffusion rate. This implies that although the contact time between migrating molecules and their surroundings is shorter at higher temperatures, the increased diffusion rate allows for more molecules to migrate within that shorter time frame. Therefore, despite the shorter contact time, the net effect of temperature on migration can be an increase. Nevertheless, it is worth noting that other factors, such as the specific properties of the migrating molecules, can also influence migration. According to Regulation (EU) 2020/784, the maximum concentration for PFOA and its salts should be 0.025 mg/kg with a maximum concentration of 1 mg/kg for a combination of PFOA-related compounds. It can be seen in Table 4 that the migration level of all compounds studied here were below these limits. 4. Conclusions A method has been developed to analyze PFAS compounds migrating from various materials, including trays made from virgin and recycled cardboards, biopolymers, papers and Teflon, sourced from different markets. These materials are commonly used as food contact materials and are believed to contain PFAS to enhance their water-repellent and oleophobic properties. The UPLC-IMS-QTOF system has proven to be a powerful tool, enabling the creation of a PFAS target list with CCS values for subsequent screening analysis. The addition of CCS as a screening parameter increases the levels of confidence in the compound assignments and reduces the number of false positives, thereby enabling increased accuracy in quantitation. The optimized extraction procedure for the Tenax migration assays produced recoveries in the range 77.5–119% with good repeatability. A total of eleven PFAS compounds were detected with higher levels of migration observed in trays obtained from a Chinese market. In this respect, a significant difference between the Spanish and Chinese trays was found, with only two compounds were detected at levels very close to their LODs in the Spanish samples. The compounds detected belong to the PFCAs, PFSAs and FOSAAs classes. The compound found to have the highest level of migration was PFOA with migration values between 3.15 and 22.3 μ g/kg. The concentrations of the other compounds considered in the migration experiments, were found to decrease with increasing chain length for each of the compound classes. Overall, the migration values were found to be between 0.86 and 22.3 μ g/kg, below the limits set by the EU Regulation for PFOA-related compounds (25 μ g/kg). Therefore all of the packaging materials tested in this study comply with the current legislation. Credit author statement Paula Vera: Conceptualization, Methodology, Validation, Investigation, Data Curation, Formal analysis, Writing - Original Draft, Writing - Review & Editing. 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