Chemometric tools to highlight NIAS in PET

Talanta, 2013

In an effort to identify non-intentionally added substances (NIAS), which is still a challenging task for analytical chemists, PET pellets, preforms and bottles were analyzed by an optimized headspace solid phase microextraction coupled to gas chromatography-mass spectrometry (HS-SPME/GC-MS). Fingerprints obtained by the proposed method were analyzed by three chemometric tools: Principal Components Analysis (PCA), Independent Components Analysis (ICA) and a multi-block method (Common Components and Specific Weights Analysis CCSWA) in order to extract pertinent variations in NIAS concentrations. Total ion current (TIC) chromatograms were used for PCA and ICA while extracted ion chromatograms (EIC) were used for CCSWA, each ion corresponding to a block. PCA managed to discriminate pellets and preforms from bottles due to several NIAS. Volatiles like 2-methyl-1,3-dioxolane, ethylene glycol, ethylbenzene and xylene were responsible for the discrimination of pellets and preforms. Less volatile compounds like linear aldehydes and phthalates were responsible for the discrimination of bottles. ICA showed more specific discriminations especially for bottles and pellets while CCSWA managed to discriminate preforms. The proposed methodology, combining HS-SPME/GC-MS with chemometric tools proved its efficiency in highlighting NIAS in PET samples in a relatively simple and fast approach compared to classical techniques.

Frontiers in sustainable food systems, 2023

The packaging has proven to be a source of some serious food contaminants, with several chemicals migrating from the food contact material into the food. Therefore, efficient means of control of the migration extend and identification of the migrating substances must be established. The necessity of migration tests has been underlined by the European Union (EU) Regulation No. 10/2011, requiring the evaluation of the presence of intentionally and non-intentionally added substances. To facilitate this purpose, highly sensitive, multi-analyte methods are required. Targeting a wide range of volatile migrating compounds, we developed and validated a GC-EI-QqQ-MS and a GC-APCI-QTOF-MS method for the simultaneous determination of 131 and 126 food packaging substances, respectively. Even though the GC-EI-QqQ-MS method presented increased sensitivity for several of the investigated compounds, covering the existing EU requirements and specific migration limits (SMLs) for all targeted analytes; the complementary high-resolution method inherently enables the possibility of further utilization of the obtained raw data among others for retrospective analysis. The applicability of both methods was tested using 95% v/v aqueous ethanol food simulant, representative for the worst foreseeable conditions of intended use for many food contact material applications. Real food packaging samples belonging to different types of plastic materials were tested toward chemical migration, utilizing different migration protocols, depending on the sample characteristics. The favorable analytical features of both methods enable their use for the direct analysis of the investigated food simulant, overcoming the need for sample preparation. Thus, labor intensive and/or time-consuming pre-concentration procedures, which would furthermore restrict the applicability of the methods to certain groups of analytes and add to the uncertainty of the overall results, could be eliminated.

Separations

Food contact materials (FCMs) are an underestimated source of food chemical contaminants and a potentially relevant route of human exposure to chemicals that are harmful to the endocrine system. Foods and water are the main sources of exposure due to contact with the packaging materials, often of polymeric nature. European Regulation 10/2011 requires migration tests on FCMs and foodstuffs to evaluate the presence of listed substances (authorized monomers and additives) and non-intentionally added substances (NIAS) not listed in the regulation and not subjected to restrictions. The tests are required to ensure the compliance of packaging materials for the contained foods. NIAS are a heterogeneous group of substances classified with a potential estrogenic or androgenic activity. Subsequently, the evaluation of the presence of these molecules in foods and water is significant. Here we present an online SPE/UHPLC-tandem MS method to quantify trace levels of NIAS in food simulants (A: aq...

Journal of Chromatography A, 2013

European Union legislation has established that plastic food contact materials shall not release primary aromatic amines (PAAs), which are toxic compounds and suspected human carcinogens. As valid alternative to existing methods for PAA determination, which are based on spectrophotometric test or targeted liquid chromatography-tandem mass spectrometry (LC-MS/MS) approaches, in this study a LC-Orbitrap-full scan-high resolution mass spectrometry (HRMS) method was devised and validated for the determination of migration levels of 22 PAAs from food contact materials, thus exploiting the specificity of accurate mass measurement. Direct injection of the simulant (acetic acid 3%, w/v) into the LC-MS system after migration, without any pre-treatment step, makes the developed method of great value for rapid screening analysis of a large number of amines. A very fast and efficient separation (<11 min) of PAAs was achieved. Detection limits in the 0.06-0.7 g kg −1 range were calculated for 17 out of 22 of the investigated PAAs, however obtaining values within 5.3 g kg −1 for the other 5 amines. Good dynamic linear ranges from two to four orders of magnitude (r 2 ≥ 0.990) were obtained and satisfying results were achieved in terms of intra-day (RSDs < 10%) and inter-day repeatability (RSDs < 17%). Trueness values in the 70 ± 1-131 ± 5% range proved reliability of the developed method for PAAs quantification also at very low concentration levels. Finally, the method was successfully applied to a range of different real plastic multilayer food packaging materials, noticing in all cases levels below the established limits of detection.

Analytica Chimica Acta, 2012

Food Chemistry, 2021

A simple and fast method was developed for the simultaneous determination of 75 plastic food contact material (FCM) in liquid food simulants, at levels of a few ng g − 1. The method employs an optimised salt-assisted liquid-liquid extraction for all EU-regulated ethanol/H 2 O food simulants, in the presence of 10% NaCl (simulants A and C) or 5% NaCl (simulant D1), and dichloromethane as the extracting solvent. Gas chromatography with triple-quad MS operating in multiple reaction monitoring acquisition was used, applying isotope dilution with selected deuterated compounds. Adequate sensitivity was demonstrated for all analytes. The results also showed sufficient accuracy for the majority of substances, with recoveries of 70-120% and repeatability (expressed as relative standard deviations, RSDs) smaller than 15%. The method was applied to the analysis of FCM multilayer items after undergoing migration testing according to the specifications of the current EU legislation in force.

Journal of Mass Spectrometry, 2015

This work presents a strategy for elucidation of unknown migrants from plastic food contact materials (baby bottles) using a combination of analytical techniques in an untargeted approach. First, gas chromatography (GC) coupled to mass spectrometry (MS) in electron ionization (EI) mode was used to identify migrants through spectral library matching. When no acceptable match was obtained, a second analysis by GC-(EI) high resolution mass spectrometry (HRMS) time-of-flight (TOF) was applied to obtain accurate mass fragmentation spectra and isotopic patterns. Databases were then searched to find a possible elemental composition for the unknown compounds. Finally, a GC hybrid quadrupole QTOF-MS with an atmospheric pressure chemical ionization (APCI) source was used to obtain the molecular ion or the protonated molecule. Accurate mass data also provided additional information on the fragmentation behaviour as two acquisition functions with different collision energies were available (MS E approach). In the low energy (LE) function, limited fragmentation took place, whereas for the high energy (HE) function, fragmentation was enhanced. For less volatile unknowns, ultra-high pressure liquid chromatography (UHPLC)-QTOF-MS was additionally applied. Using a home-made database containing common migrating compounds and plastic additives, tentative identification was made for several positive findings based on accurate mass of the (de)protonated molecule, product ion fragments and characteristic isotopic ions. Six illustrative examples are shown to demonstrate the modus operandi and the difficulties encountered during identification. The combination of these techniques was proven to be a powerful tool for the elucidation of unknown migrating compounds from plastic baby bottles.

Journal of Chromatography A, 2003

The quantification of volatile organic compounds (VOCs) in flexible multilayer packaging materials using headspace solid-phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS) was studied. The analytes include 22 compounds such as aldehydes, ketones, carboxylic acids and hydrocarbons formed by thermooxidative degradation of polyethylene during the extrusion coating process in the manufacture of the packaging, and many of them are involved in the unpleasant and undesirable odour of these materials. External standard calibration using a solution of the analytes in an appropriate solvent was the first approach studied. Aqueous solutions of the analytes provided low reproducibility and the reduction of aldehydes to alcohols under the HS-SPME conditions. Hexadecane was chosen as the solvent since its polarity is similar to that of polyethylene and its volatility is lower than that of the analytes. However, hexadecane should be added to the sample before the analysis as it modifies the absorption capacity of the fibre. A 75-mm Carboxen-poly(dimethylsiloxane) fibre was used to extract the VOCs from the headspace above the packaging in a 15-ml sealed vial at 100 8C after 5 min of preincubation. The influence of the extraction time on the amount extracted was studied for a standard solution of the analytes in hexadecane, together with the influence of the volume of the standard solution and the amount of the sample placed in the vial. Standard addition and multiple HS-SPME were also studied as calibration methods and the results obtained in the quantitative analysis of a packaging material were compared.

Analytical and Bioanalytical Chemistry, 2015

Biodegradable packagings are made by combination of several materials creating a multilayer with the properties needed. Each material, including the adhesive, could contain substances that could migrate to the food. In this work, gas chromatography coupled with mass spectrometry and ultra-high-pressure liquid chromatography coupled with quadrupole time-of-flight mass spectrometry were used to identify the biodegradable adhesive compounds. Five of the 13 compounds identified were nonintentionally added substances; they were neoformed compounds created by the reaction of added compounds in the adhesive. Moreover, the migration of the compounds through four different biodegradable materials-paper, polylactic acid, ecovio®, and polyvinyl alcohol-was studied for the first time. Three of the 13 compounds identified in the adhesive migrated from the adhesive to Tenax®, which was used as a solid food simulant. One of them, 2,4,7,9-tetramethyl-5-decyne-4,7-diol, was an intentionally added substance, and the other two were 1,6d i o x a c y c l o d o d e c a n e-7 , 1 2-d i o n e a n d 1 , 6 , 1 3 , 1 8tetraoxacyclotetracosane-7,12,19,24-tetraone, which were nonintentionally added substances identified in this work. Higher migration values (ranging from 0.81 to 2.07 mg/kg) were observed for migration through ecovio® than through the multilayer made by combination of ecovio® and polyvinyl alcohol (0.07-0.39 mg/kg) owing to the barrier effect provided by polyvinyl alcohol. The migration values for migration through paper and polylactic acid were below the limits of detection. Keywords Ultra-high-pressure liquid chromatography coupled with quadrupole time-of-flight mass spectrometry. Biodegradable packaging. Nonintentionally added substances. Migration