A Salting-out Liquid-Liquid extraction (SALLE) for the analysis of caprolactam and 2,4-di-tert butyl phenol in water and food simulants. Study of the salinity effect to specific migration from food contact materials.

Caprolactam and 2,4-di-tert-butyl phenol (2,4-DTBP) are substances typically found in some food contact materials (FCMs). They are known to often migrate into food, and are difficult to analyse in liquid food simulants using GC. In this work a simple salting-out Liquid-Liquid Extraction (SALLE) for the analysis of both substances in water and the official food simulant A (10 % v/v ethanol, Regulation (EU) No. 10/2011) is presented. The method, which included analytical determination by GC-MS, was optimized and validated to ensure sufficient analytical quality. The method's LOQs allowed the proper quantification of caprolactam at its EU legislative limit (15 mg kg-1). For 2,4-DTBP the method also revealed good sensitivity, although no official limits have been established yet. Linear regression coefficients (R2) were in all cases higher than 0.999, and recoveries ranged from 87 % and 95% for caprolactam and 2,4-DTBP, respectively. Precision was also acceptable, with the RSDs (%) below 12 %. The method proved to be adequate to be used for routine analysis. The presence of salt during migration of caprolactam and 2,4-DTBP was also investigated in this work. Polyamide/polyethylene FCM multilayer films have been tested with water and simulant A, containing different amounts of NaCl (up to 15 % m/v), and applying different migration conditions (temperature and time). The results indicated that salinity plays an important effect on the migration of caprolactam, with the presence of salt reducing its migration in case of water and increasing it in case of simulant A. These preliminary results seem to indicate that migration testing should consider not only the well-known fatty content of a food, but also its salinity content, as it may end up affecting drastically the migration of polar substances.

Determination of primary aromatic amines in cold water extract of coloured paper napkin samples by liquid chromatography-tandem mass spectrometry.

The aim of this study was the optimisation of a multi-analyte method for the analysis of primary aromatic amines (PAAs) from napkins in order to support official controls and food safety. We developed a UHPLC-MS/MS method for the simultaneous determination of 36 toxicologically relevant PAAs for paper and board. Good regression coefficients of the calibration curves in a range of 0.992-0.999 and reproducibilities in a range of 2.3-15% were obtained. Limits of detections (LODs) were in the range of 0.03-1.4 µg l(-1) and recoveries were in a range of 21-110% for all the amines. A total of 93 coloured paper napkin samples from different European countries were bought and extracted with water to determine the PAAs. The results showed that 42 of 93 samples contained at least one PAA. More than half of the detected PAAs are considered as toxic, carcinogenic or probably carcinogenic to humans by the International Agency for Research on Cancer (IARC), or are classified as such in the European Union legislation on chemicals. Summed concentrations of PAAs in seven samples were higher than 10 µg l(-1), the limit of summed PAA in the European Union plastic food contact material regulation. Also, eight PAAs, classified as Category 1A and 1B carcinogen in the European Union legislation of chemicals, were detected at concentrations higher than 2 µg l(-1), exceeding the limit proposed by the Federal Institute for Risk Assessment in Germany. Aniline (n = 14) was most frequently present in higher concentrations followed by o-toluidine, o-anisidine, 2,4-dimethylaniline and 4-aminoazobenzene. Red, orange, yellow and multicoloured paper napkins contained the highest concentrations of total PAAs (> 10 µg l(-1)). Although the European Union has not harmonised the legislation of paper and board materials and, thus, there is no specific migration limit for PAAs from paper napkins, the present study showed that coloured paper napkins can contain toxic and carcinogenic PAAs at concentrations that are relevant for monitoring.

Determination of key diffusion and partition parameters and their use in migration modelling of benzophenone from low-density polyethylene (LDPE) into different foodstuffs.

The mass transport process (migration) of a model substance, benzophenone (BZP), from LDPE into selected foodstuffs at three temperatures was studied. A mathematical model based on Fick's Second Law of Diffusion was used to simulate the migration process and a good correlation between experimental and predicted values was found. The acquired results contribute to a better understanding of this phenomenon and the parameters so-derived were incorporated into the migration module of the recently launched FACET tool (Flavourings, Additives and Food Contact Materials Exposure Tool). The migration tests were carried out at different time-temperature conditions, and BZP was extracted from LDPE and analysed by HPLC-DAD. With all data, the parameters for migration modelling (diffusion and partition coefficients) were calculated. Results showed that the diffusion coefficients (within both the polymer and the foodstuff) are greatly affected by the temperature and food's physical state, whereas the partition coefficient was affected significantly only by food characteristics, particularly fat content.

Solid-phase microextraction/gas chromatography-mass spectrometry method optimization for characterization of surface adsorption forces of nanoparticles.

A complete characterization of the different physico-chemical properties of nanoparticles (NPs) is necessary for the evaluation of their impact on health and environment. Among these properties, the surface characterization of the nanomaterial is the least developed and in many cases limited to the measurement of surface composition and zetapotential. The biological surface adsorption index approach (BSAI) for characterization of surface adsorption properties of NPs has recently been introduced (Xia et al. Nat Nanotechnol 5:671-675, 2010; Xia et al. ACS Nano 5(11):9074-9081, 2011). The BSAI approach offers in principle the possibility to characterize the different interaction forces exerted between a NP's surface and an organic--and by extension biological--entity. The present work further develops the BSAI approach and optimizes a solid-phase microextraction gas chromatography-mass spectrometry (SPME/GC-MS) method which, as an outcome, gives a better-defined quantification of the adsorption properties on NPs. We investigated the various aspects of the SPME/GC-MS method, including kinetics of adsorption of probe compounds on SPME fiber, kinetic of adsorption of probe compounds on NP's surface, and optimization of NP's concentration. The optimized conditions were then tested on 33 probe compounds and on Au NPs (15 nm) and SiO2 NPs (50 nm). The procedure allowed the identification of three compounds adsorbed by silica NPs and nine compounds by Au NPs, with equilibrium times which varied between 30 min and 12 h. Adsorption coefficients of 4.66 ± 0.23 and 4.44 ± 0.26 were calculated for 1-methylnaphtalene and biphenyl, compared to literature values of 4.89 and 5.18, respectively. The results demonstrated that the detailed optimization of the SPME/GC-MS method under various conditions is a critical factor and a prerequisite to the application of the BSAI approach as a tool to characterize surface adsorption properties of NPs and therefore to draw any further conclusions on their potential impact on health.

Optimisation of an analytical method and results from the inter-laboratory comparison of the migration of regulated substances from food packaging into the new mandatory European Union simulant for dry foodstuffs.

This paper presents the outcome of the development, optimisation and validation at European Union level of an analytical method for using poly(2,6-diphenyl phenylene oxide--PPPO), which is stipulated in Regulation (EU) No. 10/2011, as food simulant E for testing specific migration from plastics into dry foodstuffs. Two methods for fortifying respectively PPPO and a low-density polyethylene (LDPE) film with surrogate substances that are relevant to food contact were developed. A protocol for cleaning the PPPO and an efficient analytical method were developed for the quantification of butylhydroxytoluene (BHT), benzophenone (BP), diisobutylphthalate (DiBP), bis(2-ethylhexyl) adipate (DEHA) and 1,2-cyclohexanedicarboxylic acid, diisononyl ester (DINCH) from PPPO. A protocol for a migration test from plastics using small migration cells was also developed. The method was validated by an inter-laboratory comparison (ILC) with 16 national reference laboratories for food contact materials in the European Union. This allowed for the first time data to be obtained on the precision and laboratory performance of both migration and quantification. The results showed that the validation ILC was successful even when taking into account the complexity of the exercise. The results showed that the method performance was 7-9% repeatability standard deviation (rSD) for most substances (regardless of concentration), with 12% rSD for the high level of BHT and for DiBP at very low levels. The reproducibility standard deviation results for the 16 European Union laboratories were in the range of 20-30% for the quantification from PPPO (for the three levels of concentrations of the five substances) and 15-40% from migration experiments from the fortified plastic at 60°C for 10 days and subsequent quantification. Considering the lack of data previously available in the literature, this work has demonstrated that the validation of a method is possible both for migration from a film and for quantification into a corresponding simulant for specific migration.

Overall migration and kinetics of release of antioxidant compounds from citrus extract-based active packaging.

Overall migration (OM) tests were conducted on an antioxidant active packaging prepared by coating plasma pretreated and untreated polyethylene terepthalate (PET) trays with a citrus extract. The release of antioxidant compounds into food simulants was measured to permit their subtraction from OM values in line with active packaging legislation. The results demonstrated the compliance of the packaging with the limit for OM for plastic material in contact with food. The validity of the procedure for OM in aqueous food simulants was questioned, with the loss of volatile compounds during evaporation of the simulant resulting in an underestimation of total compounds released. The study showed a total release of 75% of the citrus extract coating into water and 25% into oil, which decreased to 45 and 12.5%, respectively, following plasma pretreatment of the trays.

Release of bisphenol A from polycarbonate: a review.

The release of Bisphenol A (BPA) from polycarbonate baby bottles into food and food simulants is reviewed in the perspective of the current intensive discussions on the risks of this substance. Potential factors that have been reported to influence the release of BPA are reviewed. Unlike most polymers polycarbonate is hydrolyzed under alkaline conditions by scale formation, residual alkaline detergents and boiled water. Data suggest that brushing of the bottle did not raise the release of BPA. Claims that used bottles release more BPA than new bottles and that mineral composition of the aqueous food simulant affect release could not be substantiated. There are indications that aminolysis of polycarbonate by milk and ethanolysis of polycarbonate by 50% ethanol might take place under relevant test conditions. The relatively few migration data following the test conditions of European food contact material legislation, comply with the specific migration limit. Two test conditions were identified that reflect real use and exposure, and might cause higher release of BPA compared to the test conditions of European food contact material legislation. Further detailed studies are necessary to verify whether these two exposure scenarios are more severe.

Migration of photoinitiators by gas phase into dry foods.

Photoinitiators are components widely used in UV-cured inks for printing food packaging. In the present study, the migration of seven photoinitiators through the vapor phase was investigated. To perform the migration test, an additive enriched polyethylene wax was used as a source to release photoinitiators. The method was applied to evaluate the migration of the photoinitiators into five selected dry foods (cake, bread, cereals, rice and pasta). The highest level of migration was found in the cake. Parameters affecting the migration process were evaluated, and high migration level was found to correlate with both the porosity and the fat content. In addition, the kinetics of migration of the photoinitiators from the additive enriched wax into the cake were studied under accelerated conditions.

Study of the migration of photoinitiators used in printed food-packaging materials into food simulants.

Photoinitiators (PIs) are used as catalyzers for inks and lacquers that are cured with ultraviolet (UV) light, and they can contaminate foodstuffs by mass transference.The aim of the present paper is to study the migration of six photoinitiators (Irgacure 184, benzophenone, Irgacure 651, Irgacure 907, ITX, and EHA) into food simulants [distilled water, 3% acetic acid (w/v) in aqueous solution, 10, 20, 30, 60 and 95% ethanol (v/v) in aqueous solution]. Migration levels of the six PIs into different food simulants were compared after a 30 day contact period with the additivated plastic. A relationship between R (ratio between log K(o/w) and MW) and total migration was found for PIs with log K(o/w) < 5. Key parameters of migration processes were calculated according to a mathematical model based on Fick's second law. Diffusion (D) and partition coefficients were estimated and compared among different simulants, temperatures, and PIs to understand better the mechanisms of the migration process and the physicochemical properties that most influence this phenomenon. For instance, at 5 degrees C, in ethanol 95% (v/v), D ranged between 4.2 x 10(-11) cm/s for Irgacure 907 and 3.0 x 10(-9) cm/s for benzophenone.

Search for a more adequate test to predict the long-term migration from the PVC gaskets of metal lids into oily foods in glass jars.

As shown previously, the conventional testing procedure for simulating long-term migration from the gaskets of metal closures into oily foods does not adequately reflect reality. It appears to be impossible to accelerate migration to the extent that the situation at the end of the shelf life of a product can be anticipated in a few days or weeks. Therefore, we investigated whether long-term migration could be extrapolated from migration rates determined for new lids. Jars were kept in the normal upright position. Since heat treatment may have a strong temporary impact, migration during the initial heating for pasteurization or sterilization and storage at ambient temperature were determined using different lids. Commercial products were recalled from sales points throughout Europe to determine the real migration over extended periods of time and for jars with differing histories. This migration was compared with data from the short-term testing to investigate whether an empirical relationship could be derived. The results show that the short-term test enables the comparison of lids and plasticizers in the initial phase of migration, but that long-term extrapolation presupposes more complex kinetic modeling. The results also demonstrate that the legal relevance of "official" testing methods should be reconsidered to avoid conflict when food contact materials comply with migration limits in the test but not in actual application.

Development of a method to study the migration of six photoinitiators into powdered milk.

The aim of the present work was to develop a rapid multimethod for the analysis of six photoinitiators (PIs) in powdered milk and to study the migration of these PIs from LDPE packaging into powdered milk. The optimized HPLC-DAD method showed high correlation coefficients (>0.9999) over a concentration range of 0.1-10.9 mg/L. The kinetics of migration of the photoinitiators from LDPE packaging into powdered milk were determined at different temperatures. The key parameters of migration phenomena (diffusion and partition coefficients) were determined. The diffusion coefficients at 5 degrees C ranged between 8.4 x 10(-12) (for ITX) and 5.1 x 10(-10) (for benzophenone) and those at 40 degrees C between 5.9 x 10(-10) (for ITX) and 6.1 x 10(-9) (for Irgacure 184). The diffusion coefficients of the six model migrants under study increased with temperature and showed a good Arrhenius relationship between 5 and 40 degrees C.