Elena Canellas

Quantitative determination of 22 primary aromatic amines by cation-exchange solid-phase extraction and liquid chromatography-mass spectrometry.

Primary aromatic amines (PAAs) have been broadly studied due to their high toxicity. In this work a method for the analysis of 22 PAAs in aqueous simulants has been developed. The method is based on a solid-phase extraction step using cation-exchange cartridges and the subsequent analysis of the extracts by ultra-high-performance liquid chromatography with mass spectrometric detection. The recoveries obtained for all the amines analyzed ranged between 81 and 109%, linear range was between 0.03 and 75 microg L(-1), with the RSD values between 4.5 and 13.4% and an average value of 7.5% and limits of detection at microg L(-1) level. The method has been applied to two real samples obtained from migration experiments of polyurethane based laminates to simulant B (water with 3% (w/v) acetic acid) which represents the worst case for the migration of aromatic amines. The main amines found in both samples were methylenedianiline isomers, obtained from the corresponding residual diisocyanates used during polyurethane adhesive polymerization. The total amine concentration found was 26 and 6.3 microg of aniline equivalents per kg of food simulant.

Partition and diffusion of volatile compounds from acrylic adhesives used for food packaging multilayers manufacturing

Partition and diffusion coefficients of volatile compounds in polymers have been broadly studied in the literature in order to provide the tools necessary to predict migration from the packaging materials to the food using the appropriate mathematical models. But often, food packaging materials are multilayer materials where several substrates are joint by adhesive layers. Little is known about the partition coefficients between adhesives and substrates used in these materials and about the diffusion coefficients in some of the materials commonly used such as paper or cardboard. All of these parameters will have a direct effect on the final migration of the compound. The objective of this work was to study the behaviour of the compounds found on the acrylic adhesives in 4 different real laminates. Partition coefficients between several types of acrylic adhesives and substrate materials (polyethylene, polypropylene, couche paper and kraft paper) were experimentally calculated. Moreover, diffusion coefficients of the compounds in these four materials were derived from experimental data. Finally, a migration test with Tenax was carried out. A wide variation of results for partition coefficients was found due to the difference on the chemical properties of the compounds studied. In fact, a relation between the coefficients and their Hildebrand solubility parameters was found. Moreover, the most relevant result found in the diffusion coefficient values was that the coefficients in paper were lower than in PE but higher than in PP. Migration results showed that only 4 out of 11 compounds were found in Tenax. Only 2,4,7,9-tetramethyldec-5-yne-4,7-diol belong to a high toxic class according to Cramer rules.

Composition of the adhesives used in food packaging multilayer materials and migration studies from packaging to food

A wide variety of adhesives can be used to manufacture multilayer food packaging materials. Since these materials are usually in direct contact with the packed food, compounds from the adhesive may migrate into it. Therefore it is important to determine the composition of the adhesives used. The main aims of this work were to determine the compounds present in the adhesives used in the food packaging, to study their migration to food simulants and finally to use these data to test a mathematical tool designed for predicting migration to food from laminates containing adhesives. For this purpose a total of 45 market samples of multilayer materials (laminates and other glued materials) produced with 29 different adhesives were studied. A total of 55 different compounds were detected in these adhesives, 57% of these compounds migrated into a dry food simulant (Tenax®) through the food contact layer. These data were also used to compare it with the theoretically estimated migration of the adhesive compounds using “upper-bound reference” values for the diffusion and partition coefficients implied in a multilayer migration model. In 93% of the cases the estimated migration results met or exceeded the experimental ones. This is an important requirement for testing the applicability of these theoretical migration estimations for compliance decisions which aim to protect the consumers health.

Atmospheric pressure gas chromatography coupled to quadrupole-time of flight mass spectrometry as a powerful tool for identification of non intentionally added substances in acrylic adhesives used in food packaging materials

Acrylic adhesives are used to manufacture multilayer laminates that are used in food packaging to form the geometric shape of the package as well as to stick labels on the packages. Once applied on the packaging adhesives can supply potential migrants that could endanger the packaged food. Adhesives are complex matrices where intentionally and non intentionally added substances are present, but the identification of the migrants is required by law. In this study atmospheric pressure gas chromatography coupled to a quadrupole hyphenated to a time of flight mass spectrometer (APGC-MS/Q-TOF) has been explored for identification of unknowns coming from three different acrylic adhesives. The results are compared to those obtained by conventional GC-MS-Q (quadrupole). Sixteen compounds were identified by GC-MS/Q and five of them were confirmed by APGC-MS/Q-TOF as their molecular ions were found. Moreover, additional three new compounds were identified and their structure was elucidated working with the spectra obtained by APGC-MS/Q-TOF. This finding was very relevant as these compounds were biocides suspected to be allergenic and cytotoxic in humans. Migration studies were carried out using Tenax as solid food simulant and the results showed that the three acrylic adhesives tested in this work were safe for being used in food packaging materials since the migration of compounds previously identified was below the limit established in the current legislation.

Atmospheric pressure gas chromatography with quadrupole time of flight mass spectrometry for simultaneous detection and quantification of polycyclic aromatic hydrocarbons and nitro-polycyclic aromatic hydrocarbons in mosses☆

Within the family of polycyclic aromatic hydrocarbons (PAHs), nitrated derivatives are of particular interest in environmental science because they have well-known carcinogenic and mutagenic effects. They are in fact more toxic than their parent PAHs. One valuable diagnosis of atmospheric pollution can be obtained using biomonitors such as mosses. These biomonitors can provide information about air pollution over long periods of time in wilderness areas. Thus, they can serve as monitors of the atmospheric transport of pollutants. In this study, atmospheric pressure gas chromatography coupled to a quadrupole hyphenated to a time of flight mass spectrometer (APGC-MS/Q-TOF) has been examined for the identification of target analytes (15 PAHs and 8 NPAHs) for subsequent use in the analysis of mosses. Working ranges in low μg g(-1) concentration levels were obtained with most correlation coefficients higher than 0.999. All LODs were in the 0.007-0.035μg g(-1) range and higher LODs (0.035μg g(-1)) were obtained for the less volatile PAHs with higher mass and retention times: benzo(g,h,i)perylene, dibenz(a,h)anthracene and indeno(1,2,3-c,d)pyrene. These LODs are of importance for the intended use, biomonitoring, especially taking into account that NPAHs are commonly found at very low concentration levels. Recoveries from mosses ranged from 75 to 98%. Intraday and interday precision ranged from 1.8 to 11.1% RSD and from 2.4 to 16.7% RSD, respectively. Very low concentrations of NPAHs were found in mosses compared to those of PAHs. All these data were used for pattern recognition of the pollutant source. The results are shown and discussed.

New UPLC coupled to mass spectrometry approaches for screening of non-volatile compounds as potential migrants from adhesives used in food packaging materials

The objective of this study was to identify the non-volatile compounds as potential migrants from adhesives used in food packaging. A number of the current acrylic adhesive formulations were extracted and prepared for analysis. The extracts were screened using ultra-performance liquid chromatography coupled to a time-of-flight mass spectrometer detector (UPLC-TOF-MS). This approach allowed the identification of several components by a combination of exact mass and in-source collision induced dissociation (CID). Due to the lack of freely available information on adhesive formulations further analyses were undertaken using ultra-performance liquid chromatography coupled to high definition mass spectrometry (UPLC-HDMS). Using the Mass Fragment tool to interrogate fragmentation data, a wide series of compounds were identified, demonstrating the usefulness and importance of these tools for difficult problems. Moreover, using several packaging materials containing adhesives, qualitative migration tests were performed with Tenax as a food simulant. Several non-volatile compounds were identified as well in the Tenax which emphasizes the importance of this work and demonstrates that even the non-volatile compounds have the potential to migrate into food which is in contact with packaging materials. The main characteristics of the screening study and the results obtained are shown and discussed.

Analytical methods for the screening of potential volatile migrants from acrylic-base adhesives used in food-contact materials.

Two different analytical techniques were studied for screening the volatile compounds present in pure adhesives and those from the adhesives in different laminates. Three different adhesive formulations were used for the study, all acrylic-based and supplied by different producers. Laminates with polypropylene and paper, polypropylene and polyethylene, and aluminium and polyethylene as substrates were prepared and studied. Adhesives themselves were acetonitrile extracted and volatiles identified by time-of-flight mass spectrometry based on accurate mass measurement of molecular and main fragments. The volatiles in the films themselves were determined by a headspace solid-phase microextraction analysis followed by gas chromatography-mass spectrometry. Significant differences were found within the adhesive formulations. Compounds detected in the screening were assessed in terms of migration through the laminate polypropylene and paper into polyethylene used as a matrix-simulating food. The concentration of the compounds in the polyethylene ranged from 0.04 to 1.6 µg dm−2 in the polypropylene side, and from 0.27 to 28 µg dm−2 in the paper side. The most toxic compound detected in the screening, 2,4,7,9-tetramethyl-5-decyne-4, was not found in any of the sides. Analytical features were also calculated to provide the conditions for quantitative purposes. Sensitivity was at low ng dm−2 of polyethylene and the relative standard deviation was below 10%.

Migration of non intentionally added substances from adhesives by UPLC–Q‐TOF/MS and the role of EVOH to avoid migration in multilayer packaging materials

Polyurethane adhesives are commonly used to laminate multilayer packaging materials for food. Since these materials are in direct contact with the food, compounds could migrate from adhesive into it. For this reason, it is important to identify all the potential migrants and verify their migration. Ultra-high performance liquid chromatography-quadrupole time-of-flight-mass spectrometry analyses and ChemSpider database are used to identify the potential migrants from polyurethane adhesives, and these techniques were demonstrated to be very powerful and useful tools for this purpose. Migration tests were carried out using Tenax® as food simulant. Nine out of fifteen non-volatile compounds, identified in the cured adhesives, migrated. Most of them were identified as cyclic compounds, adipic based, which is the most commonly used monomer to make the polyester/polyol resins for polyurethane bi-component adhesives. In this work, the use of EvOH layer in several multilayer materials to minimize or avoid migration was evaluated too.

Migration of odorous compounds from adhesives used in market samples of food packaging materials by chromatography olfactometry and mass spectrometry (GC-O-MS).

Adhesives are commonly used in the manufacture of multilayer food packaging materials. Although they are not in direct contact with the packed food, their compounds may migrate from the adhesive through the substrates to the food. The aim of this work is to determine the migrant concentration in order to evaluate the possible human risk and also to determine if this migration could affect the organoleptic properties of packed food. For this purpose, a total of 12 market samples of multilayer materials (laminates) for packaging dry food (tomatoes, cakes, cookies, breadcrumbs, flour or salt) or fresh food (pizza and pastry) produced with 5 different adhesives were analysed by GC-O-MS. A total of 25 different compounds from adhesives were detected in these laminates. Seventy-six percentage of these compounds migrated into a dry food simulant (Tenax®). Furthermore, compounds with concentrations below the MS detection limit were detected by sniffers with a high modified frequency (MF%). Acetic acid, butyric acid and cyclohexanol with vinegar, cheese and camphor odours were the most abundant compounds. All migration data were below the specific migration limits (SML) and threshold toxicological concern (TTC) recommended values according to the Cramer classification.

Identification and quantification of odorous compounds from adhesives used in food packaging materials by headspace solid phase extraction and headspace solid phase microextraction coupled to gas chromatography–olfactometry–mass spectrometry

Adhesives are often responsible for off-flavors in food in contact with packaging. The aim of this investigation was to identify by GC-O-MS the odorous compounds in five different types of adhesive (hotmelt, vinyl acetate ethylene, starch, polyvinyl acetate and acrylic) used in food packaging. In order to obtain a substantial number of compounds, they were extracted by two complementary extraction methods: HS-SPE and HS-SPME. Fifteen minutes extraction time using PDMS fiber for hotmelt adhesive and DVD/CAR/PDMS fiber for the other adhesives were the best conditions for defining a representative solvent-free adhesive extract using a rapid and simple D-GC-O technique. Thirty-three compounds were identified by GC-O-MS. These include butyric acid, acetic acid, methyl butyrate, 1-butanol and nonanal, which were present in most of the adhesives under study producing cheesy, rancid, sour, medicinal and green aromas, respectively. The concentrations were determined, the most abundant compound being acetic acid with concentrations from 22.9 to 8930 μg g(-1) of adhesive.