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. Copyright © 2013 John Wiley & Sons, Ltd.     

Atmospheric pressure gas chromatography coupled to quadrupole‐time of flight mass spectrometry as a tool for identification of volatile migrants from autoadhesive labels used for direct food contact

Pressure‐sensitive adhesives (PSA) are used to manufacture labels that are applied directly on the food. These adhesives could contain not only intentionally added compounds (IAS) to the adhesive formula but also non‐intentionally added substances (NIAS), due to the impurities from the raw materials used, decomposition of the initial components or from chemical interactions between them. These compounds could migrate to the food and contaminate it. In this study, gas chromatography coupled with mass spectrometry (GC‐MS/Q) and atmospheric pressure gas chromatography coupled to a quadrupole hyphenated to a time of flight mass spectrometer (APGC‐MS/Q‐TOF) have been used for identification of unknown compounds and NIAS coming from a PSA. Seven compounds were identified by GC‐MS/Q, and other eight compounds remained initially unknown. The structure of these eight new compounds was elucidated by working with the spectra obtained by APGC‐MS/Q‐TOF. Finally, two different migration studies were carried out. The first one with Tenax as solid food simulant in contact with the paper label containing the adhesive and the second one with isooctane filled in a natural pork intestine where the label containing the adhesive was applied on the external side. The results are shown and discussed. Copyright © 2014 John Wiley & Sons, Ltd.     

Identification and migration of degradation compounds from irradiation of multilayer polyamide 6 films for meat foodstuffs and cheese

The aim of this work was to identify the degradation compounds produced during irradiation of multilayer polyamide 6 (PA-6) films and to study their migration into water and 95% ethanol food simulant. After irradiation of multilayer PA-6 films at 3, 7 and 12 kGy, degradation compounds were extracted using solid-phase microextraction, for which the time and temperature of extraction and stirring were optimized, and identified by gas chromatography–mass spectrometry. Caprolactam, 2-cyclopentylcyclopentanone and aldehydes, among other compounds, were identified in the headspace of the films. Polydimethylsiloxane was considered the best fiber for extraction. The optimum conditions of time, temperature and stirring to extract the compounds were 20 min, 80 °C and 225 rpm. For validation purposes, the compounds were quantified in water and 95% ethanol and the results showed high sensitivity, good precision and accuracy. Migration of compounds from irradiated and non-irradiated multilayer PA-6 films into water and 95% ethanol food simulants was carried out at 40 °C for 10 days. The method was efficient for the quantification of decaldehyde, 2-cyclopentylcyclopentanone and caprolactam that migrated from multilayer PA-6 films into food simulants.     

纸基食品接触材料中4-肉桂苯酚和水杨酸对叔丁基苯酯向干性食品模拟物TenaxTA的迁移

以纸基食品接触材料中的4-肉桂苯酚(CP)和水杨酸对叔丁基苯酯(TBS)为模拟迁移物,对其向干性食品模拟物Tenax TA中的迁移规律采用超高效液相色谱结合荧光检测(UPLC-FLR)方法进行了研究。在不同温度下对CP和TBS的迁移动力学进行了考察,并对其在封闭环境和敞开环境下的迁移率进行对比研究。通过设计不同质量的Tenax TA接触直径为3.5 cm圆片样品的迁移试验,探索了迁移试验中合适的模拟物质量/接触材料面积比条件。系列试验结果表明,迁移物迁移时间越长,迁移温度越高,相应的迁移率就越高;在高的迁移温度下,迁移物在Tenax TA上的解吸会导致迁移率的下降;在封闭条件下CP和TBS的迁移率要高于敞开条件下的迁移率;迁移试验中,4.16 g/dm²的模拟物质量/接触材料面积比是利用干性食品模拟物进行食品接触材料暴露评估的合适的迁移试验条件。密闭条件下市售的8种食品接触材料干性食品模拟物迁移实验研究表明,TBS存在于用于包装坚果类食品的包装纸中,含量为15.54 mg/kg。     

Aromatic amines from polyurethane adhesives in food packaging: The challenge of identification and pattern recognition using Quadrupole-Time of Flight-Mass Spectrometry

Toxic primary aromatic amines (PAAs) are reaction products from residual isocyanates in polyurethane adhesives. The maximum migration level of the total sum of PAAs is 10 ng g⁻¹ of food. This paper reports on a method for quantification of 18 PAAs by UHPLC–MS/MS that was optimised and applied to a series of industrial laminates prepared from polyurethane adhesives. Non-intentionally added substances (NIAS), impurities and other migrants were identified by Q-TOF/MS^E. A comparison of the quantitative values obtained by the colorimetric method using NEDA and by UHPLC–MS/MS confirmed that the first method can overestimate the quantification of PAAs. This could be attributed to the impurities and other NIAS present in the plastic laminate. Values of R² in the analytical characteristics of UHPLC–MS/MS were obtained, the best value being 0.9964 and the most unfavourable 0.7626. The detection limit (LOD) and the quantification limit (LOQ) were 2 pg g⁻¹ and 7 pg g⁻¹, respectively. The stability of the PAAs over time in the acidic simulant in contact with the plastic laminate is also reported.     

Migration of organic compounds from a multilayer plastic–paper material intended for food packaging

This paper deals with the study of the kinetic migration of a series of organic compounds representative of potential contaminants in packaging materials and used as surrogates (o-xylene, acetophenone, dodecane, naphthalene, 2,3,4-trichloroanisole, benzophenone, isomeric mix of diisopropylnaphthalene, diisobutyl phthalate and methyl stearate). Migration to one side of a solid simulant, Tenax, also referred to as MPPO (modified polyphenylene oxide), was investigated in this study. One spiked sample of multilayer material was used to optimise the extraction procedures for the multilayer paper-based material and the Tenax as well as to perform kinetic migration studies. Three sequential extractions using ethanol were necessary for the strips of the multilayer material but only one extraction was necessary for the solid simulant to obtain >70% recovery of the surrogates. These results enabled us to specify the extraction requirements of the multilayer sample and the solid simulant and as well as those of the migration tests at high temperature using Tenax as solid simulant. The matrix effect associated with the extraction of the contaminants from the multilayer sample is also discussed.     

MALDI-MS and colorimetric analysis of diisocyanate and polyol migrants from model polyurethane adhesives used in food packaging

The identification of the migrants, into food simulants, from a series of polyurethane adhesives used in the manufacture of plastic film laminates for use in common food packaging is described. Commercial materials, based on four different model adhesive systems, were prepared by an industrial collaborator. The MALDI-MS fingerprint patterns of the three polyether and one polyester polyol components of these adhesives were obtained for reference purposes. The decrease in the level of diisocyanate as a migrant versus time after lamination was confirmed by colorimetric measurements. The migration of the standard polyol samples through polyethylene pouches into water at 70 degrees C has been demonstrated and also the attenuation effect for different polyols. Cured laminates in the form of pouches were used to carry out the migration experiments into distilled water, inside the pouch, at 70 degrees C over a period of 2 h. Comparison of the migration results from the food packaging laminates with those from the polyethylene film confirmed the migration of unreacted polyol components for the polyether-based systems. Cyclic oligomers from the polyol starting materials were identified as the migrants from the polyester-based adhesive.     

Ultra‐high pressure LC for astaxanthin determination in shrimp by‐products and active food packaging

Nowadays, there is increasing interest in natural antioxidants from food by‐products. Astaxanthin is a potent antioxidant and one of the major carotenoids in crustaceans and salmonids. An ultra‐high pressure liquid chromatographic method was developed and validated for the determination of astaxanthin in shrimp by‐products, and its migration from new packaging materials to food simulants was also studied. The method uses an UPLC® BEH guard‐column (2.1 × 5 mm, 1.7 µm particle size) and an UPLC® BEH analytical column (2.1 × 50 mm, 1.7 µm particle size). Chromatographic separation was achieved using a programmed gradient mobile phase consisting of (A) acetonitrile–methanol (containing 0.05 m ammonium acetate)–dichloromethane (75:20:5, v/v/v) and (B) ultrapure water. This method was evaluated with respect to validation parameters such as linearity, precision, limit of detection, limit of quantification and recovery. Low‐density polyethylene films were prepared with different amounts of the lipid fraction of fermented shrimp waste by extrusion, and migration was evaluated into food simulants (isooctane and ethanol 95%, v/v). Migration was not detected under the tested conditions. Copyright © 2012 John Wiley & Sons, Ltd.     

Effect of gamma irradiation on caprolactam migration from multilayer polyamide 6 films into food simulants: development and validation of a gas chromatographic method

A GC method to determine caprolactam in water, 15% ethanol, and olive oil food simulants was developed and validated. Linear ranges varied from 0.96 to 642.82 microg/mL for water, 0.64 to 800.32 microg/mL for 15% ethanol, and 1.06 to 1062.34 microg/g for olive oil, with correlation coefficients higher than 0.999. Method precision studies showed RSD values lower than 5.45%, while method accuracy studies showed recovery from 72 to 111% for all simulants. The effect of gamma irradiation on caprolactam migration from multilayer polyamide 6 (PA-6) films intended for cheese into water, 15% ethanol, olive oil, and 3% acetic acid simulants was also studied. For migration assay, non-irradiated and irradiated (12 kGy) films were placed in contact with the simulant and exposed at 40 degrees C for 10 days. The validated method was used to quantify caprolactam migration from multilayer PA-6 films into the simulants, which ranged from 1.03 to 7.59 mg/kg for non-irradiated films, and from 4.82 to 11.32 mg/kg for irradiated films. Irradiation caused almost no changes in caprolactam levels, with the exception of olive oil, which showed an increase in the caprolactam level. All multilayer PA-6 films were in accordance with the requirements of the legislation for caprolactam migration.     

超高效液相色谱/静电场轨道阱高分辨质谱法同时测定塑料食品接触材料中光稳定剂和抗氧化剂的特定迁移量

建立了超高效液相色谱/静电场轨道阱高分辨质谱同时测定塑料食品接触材料中多种光稳定剂和抗氧化剂特定迁移量的方法。采用30 g/L乙酸、体积分数分别为10%、20%、50%的乙醇和油类模拟物(异辛烷)这5种食品模拟物对塑料食品接触材料进行处理,对处理液进行超高效液相色谱/静电场轨道阱高分辨质谱分析,外标法定量。该方法测定的40种目标化合物在相应的范围内均具有良好的线性关系,相关系数均大于0.998,定量限为0.01~1.00μg/L。考察了上述5种食品模拟物中光稳定剂和抗氧化剂的特定迁移量,平均加标回收率为81.46%~94.53%,相对标准偏差为3.25%~9.99%。应用该方法对市售塑料食品接触材料进行了测定,结果在部分样品中检出了不同含量的光稳定剂和抗氧化剂。该方法灵敏度高,定量限低,满足塑料食品接触材料中光稳定剂和抗氧化剂特定迁移量的检测要求。     

UPLC–MS as a powerful technique for screening the nonvolatile contaminants in recycled PET

The possibility of using recycled polyethylene terephthalate as a food contact material is being seriously considered, but the potential migration of nonvolatile compounds from it must be assessed to ensure that it is safe to do so. In the study presented here, four samples of recycled PET were each exposed to three food simulants under the harsh extraction conditions stipulated by European legislation regarding migration tests. The nonvolatile compounds that migrated from them were determined by ultra performance liquid chromatography–mass spectrometry using three different cone voltages, and both positive and negative ionization modes. A total of 36 chemical compounds were detected, some of which were identified, including common additives such as N,N′-di-beta-naphthyl-p-phenylenediamine (antioxidant) and 2,4-di-tert-butyl-6-(5-chloro-2H-benzotriazol-2-yl)phenol (light stabilizer) as well as degradation compounds such as ethylene terephthalate dimers and trimers. In addition, specific migration values of three common components of polyethylene terephthalate (diethylene glycol, terephthalic acid, and isophthalic acid) were determined and found to occur at levels of <1 mg/kg—much lower than the specific migration limits stipulated by European legislation.     

Controlled loading and release of methylene blue from LbL polyurethane/poly(acrylic acid) film

The layer‐by‐layer (LbL) assembled multilayer films are widely used in the biomedical field for the controlled drug delivery. Here, multilayer films were assembled by LbL technique through alternating deposition of cationic polyurethane (PU) and poly(acrylic acid) (PAA) on glass slides. Methylene blue (MB) was used as a model drug to investigate the loading and release ability of the prepared multilayer film. The results showed that the loading rate and loading amount of MB were greatly influenced by pH value of the dye solution, and the release rate of MB was controlled both by ionic strength and pH value of immersing solution. The result also indicated that the film had a good reversibility of drug loading and release. It suggested that the PU/PAA multilayer film had potential applications in drug delivery and controlled release. Copyright © 2011 John Wiley & Sons, Ltd.     

A novel method for the determination of migration of contaminants from food contact materials

A neutron activation method has been developed for the analysis of high density polyethylene, low density polyethylene, polypropylene, polyethylene terephthalate and polystyrene food contact plastics. The method provides determination of over 50 elements at concentrations below 1 mg kg^–1. This technique has now been extended to study migration from food contact materials into standard food simulants (olive oil, acetic acid, ethanol and water). Samples of plastic are irradiated in a thermal neutron flux to produce radionuclides of the elements present in the plastic. Over a period of time the radionuclides of these elements may travel from the plastic into the food simulants, and hence the migration can be determined. Gamma ray spectrometry is performed on the simulants at the end of the test to quantify the migration. Any activity present must be due only to the migration of radionuclides of elements in the plastic and nothing else. This eliminates the need for a blank determination, which is required with existing migration methods. Preliminary studies have shown that detection limits of around 0.002 mg kg^–1 can be achieved for Sb in a retail polyethylene terephthalate (PET) bottle. This can be compared to levels of 0.005     

Migration Testing of GPPS and HIPS Polymers: Swelling Effect Caused by Food Simulants Compared to Real Foods

Migration kinetic data from general purpose polystyrene (GPPS) and high impact polystyrene (HIPS) were generated for a set of model substances as well as styrene monomer and oligomers at different temperatures (20 °C, 40 °C, 60 °C) using food simulants stipulated in the European Regulation (EU) 10/2011 and real foods like milk, cream and olive oil (20 °C, 40 °C). The extent of polymer swelling was characterized gravimetrically and visual changes of the test specimens after migration contact were recorded. Isooctane and 95% ethanol caused strong swelling and visual changes of HIPS, overestimating real migration into foods especially at high temperatures; GPPS was affected by isooctane only at 60 °C. With 50% ethanol, after 10 days contact at 60 °C or 40 °C both polymers were slightly swollen. Contrary, most of the real foods analyzed caused no detectable swelling or visual changes of the investigated polymers. This study demonstrates that the recommendations provided by EU regulations are not always in agreement with the physicochemical properties of styrenic polymers. The critical point remains the selection of adequate food simulants/testing conditions, since the high overestimation of aggressive media can lead to non-compliance of polystyrene materials even if the migration into real food would be of no concern.     

Ultra-high pressure LC determination of glucosamine in shrimp by-products and migration tests of chitosan films

Chitosan, a multiple applications molecule, was isolated from shrimp by-products by fermentation. The amount of chitosan in the solid fraction of the fermented extract was measured after its conversion in the respective glucosamine units. The procedure includes an acid hydrolysis (110 °C, 4 h with HCl 8 M) and a derivatization with 9-fluorenylmethyl chloroformate (Fmoc-Cl). Ultra-high-pressure liquid chromatography method was developed and optimized. Excellent peaks resolution was achieved in just 10 min. The method was evaluated in what concerns to validation parameters such as linearity, repeatability, quantification limit, and recovery. Migration tests of films prepared with chitosan were carried out in two simulants: ultrapure water and ethanol 95% (v/v).     

Evaluation of the migration of UV-ink photoinitiators from polyethylene food packaging by supercritical fluid chromatography combined with photodiode array detector and tandem mass spectrometry

UV-ink photoinitiators (PIs), which are used to initiate polymerization reaction for the curing of inks and lacquers, have become a kind of contaminant residues in printing plastic food packaging. The residual PIs in packaging may pose a potential threat to customers. In this work, migration behaviors of 13 PIs from a polyethylene (PE) packaging to food simulants according to regulation EU No 10/2011 were studied by supercritical fluid chromatography combined with photodiode array detector and tandem mass spectrometry (SFC-PDA-MS/MS). The method simultaneously analyzed 13 PIs within 4.5 min and was sensitively with low limits of detection of 0.02–2.16 μg/L, which could meet high throughput analysis for control the quality of food packaging. The migration results revealed that Irgacure 819, Darocure 1173 and TPO, which had low migration rates, should be preferably selected by plastic food packaging manufacture for food safety.     

Radioanalytische verfahren zur bestimmung des übertritts von packstoffbestandteilen in nahrungsmittel

The quantitative determination of the transfer of substances in the system packaging material/foodstuff is essential for the protection of the consumer and with respect to food regulations. The analytical difficulties occurring can be overcome by using food simulants and radio indicators. With the help of the radio tracer techniques described it is possible to determine the migration of an individual component of the packaging material into liquid and solid foodstuffs or their simulants. The methods show a high detection sensitivity; other substances do not interfere. This is accomplished by incorporating a radio indicator with the same chemical structure as the packaging-material component under consideration into test films or test sheets under conditions actually encountered in practice. The radio indicator must be evenly distributed in the test material. Then, parts of the radioactive test films or sheets are brought in one- or two-sided contact with the foodstuffs or their simulants using newly developed extraction and migration cells. The extracted or migrated amounts of the packaging material component are calculated from the radioactivities migrated into the contact media under the test conditions given. As an example for the application of these radio tracer techniques, investigations into the migration behaviour of the organotin stabilizer di-n-octyltin-2-ethyl-hexyl-dithioglycolate in the system rigid PVC/edible fat or test fat resp. are described. For the determination of the total components migrating from a packaging material into foodstuffs, a radio tracer method was developed making use of a¹⁴C-labelled standard triglyceride mixture—the fat simulant HB 307—¹⁴C: therefore, the sample of the packaging material is weighed before and after storage in the fat simulant HB 307—¹⁴C and the content of simulant in the stored sample is determined radioanalytically. The so-called global migrate equals the difference in weight of the sample of packaging material before and after storage in the simulant, provided, the amount of simulant absorbed by the test specimen has been subtracted previously from the weight of the stored sample. The efficiency of this method is demonstrated by determinations of the global migrates of polyvinyl chloride films containing different amounts of plasticizers and the dependence of the mean error of the single determination on the amount of global migrate is discussed.      

聚酯类食品包装材料中二氧化钛在食品模拟物中的迁移规律

采用电感耦合等离子体质谱法(ICP–MS),在不同的模拟迁移条件(模拟物、盛放温度、接触时间、乙酸浓度、使用次数等)下,研究聚酯类食品包装材料中二氧化钛在6种食品模拟物(水、4%乙酸、10%乙醇、65%乙醇、正己烷和异辛烷)中的迁移规律。结果显示:食品模拟物的属性对迁移行为有显著影响,迁移量随温度的升高及时间的延长而增加,食品的酸性越强,二氧化钛的迁移量越大。因此需适量控制聚酯类食品包装材料的反复使用次数、盛放食品时的温度和时间以降低二氧化钛迁出风险。     

UV Protective,Antioxidant, Antibacterial and Compostable Polylactic Acid Composites Containing Pristine and Chemically Modified Lignin Nanoparticles

Polylactic acid (PLA) films containing 1 wt % and 3 wt % of lignin nanoparticles (pristine (LNP), chemically modified with citric acid (caLNP) and acetylated (aLNP)) were prepared by extrusion and characterized in terms of their overall performance as food packaging materials. Morphological, mechanical, thermal, UV–Vis barrier, antioxidant and antibacterial properties were assayed; appropriate migration values in food simulants and disintegration in simulated composting conditions were also verified. The results obtained indicated that all lignin nanoparticles succeeded in conferring UV-blocking, antioxidant and antibacterial properties to the PLA films, especially at the higher filler loadings assayed. Chemical modification of the fillers partially reduced the UV protection and the antioxidant properties of the resulting composites, but it induced better nanoparticles dispersion, reduced aggregates size, enhanced ductility and improved aesthetic quality of the films through reduction of the characteristic dark color of lignin. Migration tests and disintegration assays of the nanocomposites in simulated composting conditions indicated that, irrespectively of their formulation, the multifunctional nanocomposite films prepared behaved similarly to neat PLA.     

Properties of poly(lactic acid-co-glycolic acid) film modified by blending with polyurethane

A number of poly(lactic acid-co-glycolic acid)/polyurethane (PLGA/PU) blend films with various PU mole contents were prepared by casting the polymer blend solution in chloroform. The surface morphologies of the PLGA/PU blend films were studied by scanning electron microscopy (SEM). The thermal, mechanical and chemical properties of the PLGA/PU blend films were investigated by differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), tensile tests and surface contact angle tests. The results revealed that the introduction of PU could markedly modify the properties of PLGA films.