Migration of lubricants from food packagings

Occurrence of meso/micro/nano plastics and plastic additives in food from food packaging

This chapter focuses on the occurrence of plastic constituents in food due to the contact with different types of plastic packaging, films and coatings. The type of mechanisms occurring during the contamination of food by different packaging materials are described, as well as how the type of food and packaging may influences the extent of contamination. The main types of contaminants phenomena are considered and comprehensively discussed, along with the regulations in force for the use of plastic food packaging. In addition, the types of migration phenomena and factors that may influence such migration are comprehensively highlighted. Moreover, migration components related to the packaging polymers (monomers and oligomers) and the packaging additives are individually discussed in terms of chemical structure, adverse effects on foodstuffs, health, migration factors, as well as regulated residual values of such components.

Interference of oleamide with analytical and bioassay results

During sample preparation and analysis, samples are coming in contact with different labware materials. By four unrelated analytical (phytochemical and pharmaceutical) case-studies and employing different analytical techniques, we demonstrated the potential misinterpretation of analytical results due to the use of contaminants-leaching labware during sample handling. Oleamide, a common polymer lubricant and a bioactive compound, was identified as a main analytical interference, leaching from different labware items into solvents, recognised as chemically compatible with the tested polymer material. Moreover, anti-inflammatory effect of oleamide at 100 μg mL⁻¹ and considerable pro-inflammatory effect of the plastic syringe extractables (containing oleamide) at the same level were shown in a TLR4-based bioassay. Taking these results into account, together with the fact that oleamide can be a compound of natural origin, we would like to notify the professional public regarding the possible erroneous oleamide-related analytical and bioassay results due to the use of oleamide-leaching labware. Researchers are alerted to double check the real source of oleamide (labware or natural extract), which will prevent further reporting of false results. Analysis of procedural blanks with de-novo developed UHPLC-ESI-MS method is, among some other strategies, proposed for detection of oleamide interference and avoidance of misleading results of certain analyses.

GC-MS Studies on the Contaminants in Paper-Plastic Food Packaging Materials

The residual contaminants in paper-plastic food packaging materials can migrate into both surface and inside of food, and consequently harm consumer’s health. Due to this fact, the safety of food packaging materials has attracted concerns from all over world. In this study, the residual contaminants were extracted by ethanol from paper-plastic food packaging materials under ultrasonic condition and different temperatures firstly, then the extractives were concentrated by rotary evaporator, and finally the concentrated contaminants were characterized by means of Gas Chromatography-Mass Spectrometry (GC-MS) detection. The results showed that the following contaminants are detected in the paper-plastic food packaging materials: plasticizer including dibutyl phthalate (DBP) and di-2-ethylhexyl phthalate (DEHP); antioxidants including 2,6-Di-tert-butyl-p-benzoquinone and 2,6-Di-tert-butyl-4-methylphenol (BHT), and solvents in printing ink production including n-Hexadecane and n-Heptadecane. Upon the test results, the conclusion is that more residual contaminants can be detected under high temperatures. This study is helpful for quality control of paper-plastic food packaging materials and has built basic foundation for future migration research.

Dual analysis of triglycerides from certain common lipids and seed extracts

A number of reference oils, two commercial oils, and several oil extracts from seeds of Nicotiana species were analyzed for the fatty acid content and also for triglyceride composition. The seed oils were obtained using an accelerated solvent extraction procedure, which was proven to be very efficient and reproducible. The fatty acids were analyzed after the hydrolysis of the oils, using trimethylsilylation and gas chromatography/mass spectrometry (GC/MS) analysis. The levels of sixteen molecular species of triglycerides in the oils were measured after GC separation using MS for identification and flame ionization detection (FID) for quantitation. The results for the fatty acids and those for triglycerides were combined to generate uniform information regarding the composition of the analyzed oils. For a number of oils, the individual triglyceride quantitation and mass spectra were reported for the first time. The study showed that in some cases, oils with similar fatty acid content do not have the same triglycerides profile. The fatty acids and triglycerides profile for selected Nicotiana species were described for the first time in the literature.

Application of liquid chromatography in polymer non-ionic antistatic additives analysis

This article investigates the applicability of HPLC-UV, ultra performance LC-evaporative light-scattering detection (UPLC-ELSD), HPLC-ESI(+)-MS and HPLC-hybrid linear ion trap (LTQ) Orbitrap MS for the analysis of different non-ionic antistatic additives, Span 20, Span 60, Span 65, Span 80, Span 85 (sorbitan fatty acid esters), Atmer 129 (glycerol fatty acid ester) and Atmer 163 (ethoxylated alkylamine). Several alkyl chain length or different degrees of esterification of polyol derivatives can be present in commercial mixtures of these polymer additives. Therefore, their identification and quantification is complicated. Qualitative composition of the studied compounds was analysed by MS. HPLC-UV, UPLC-ELSD and HPLC-LTQ Orbitrap MS methods were applied to the quantitative determination of the different Spans, Atmer 129 and Atmer 163, respectively. Quality parameters of these methods were established and no derivatization was necessary.

Determination of N,N'-ethylenebisstearamide additive in polymer by normal phase liquid chromatography with evaporative light scattering detection

A new method for N,N'-ethylenebisstearamide (EBS) analysis was developed and validated in normal phase-HP liquid chromatography (NP-HPLC) with diol column at 50 degrees C with 100% CHCl(3) at 1 mL min(-1) and evaporative light scattering detection with elution time at 3.0 min. EBS solubility was the best at 0.80 gL(-1) in CHCl(3)/methanol 90:10. The molecular structure of commercial samples of EBS was determined by GC-MS which ascertained that the main structure is C18/C18 at approximately 45%. The remaining part was constituted by molecules with different alkyl chain length. The HPLC quantification method was proved linear (r=0.9983), accurate (99.6%) and precise (1.95%). Limit of quantification (LOQ) and limit of detection (LOD) were equal to 2.0 and 0.8 microg mL(-1), respectively. The suitability of this method was assessed with a dissolution/precipitation extraction procedure of EBS from ethylene vinyl acetate (EVA) polymer which showed that other additives and polymer do not interfere with EBS analysis. The intra-day and day-to-day precisions of extraction method were equal to 9.1% and 9.9%, respectively.

Sample preparation and gas chromatography of primary fatty acid amides

A method for the isolation of bio-active primary fatty acid amides (PFAM's) from total lipid extract by solid-phase extraction (SPE) was developed and validated. The lowest mass of amide to be loaded and recovered by this method was detected as 0.5 microg using 500 mg of normal phase adsorbent. The isolated PFAM's were separated and quantified by GC/MS and percent recoveries were calculated. An HP-5MS column was able to provide base line separation between the saturated and unsaturated PFAM's whereas clear resolution between geometric and positional isomers having the same number of carbons was obtained using a BPX70 column. The separated amides were all 18 carbon analogs of cis-9-octadecenoamide (oleamide). Detection limits in the single ion monitoring mode were found to be on the order of 10 pg in a 1 microl injection. Solid phase extraction of amides from total lipid extract before GC/MS analysis provides clean detection and interference free analysis.

Study of the analysis of alkoxyglycerols and other non-polar lipids by liquid chromatography coupled with evaporative light scattering detector

An HPLC method with evaporative light scattering detection (ELSD) for the simultaneous analysis of various lipid classes, particularly alkoxyglycerols and acylglycerols with very similar structure and polarity, has been developed. These lipid classes are frequently found in numerous fats and oils such as shark liver oils and can serve as substrates for lipase-catalyzed reactions. This method utilizes a silica column and a gradient elution of isooctane, methyl tert-butyl ether and 2-propanol in different proportions. Separation between squalene, sterol esters, and fatty acid ethyl esters has been achieved in a time of analysis slightly higher than 8 min. In addition, a good resolution between 1,3-diacylglycerols and free sterols was also attained in the same run, with a broad range of concentrations. Excellent precision regarding the retention times was obtained. The limit of detection for the different lipid classes studied was below 1 microg. Intra-day and inter-day variation of retention times and areas was also evaluated. The relative standard deviation of intra-day variation for retention times and areas never exceeded of 0.1 and 10, respectively. The HPLC-ELSD method was also optimized to separate and quantify the hydrolysis products of alkoxyglycerols and acylglycerols (mono-esterified and non-esterified alkoxyglycerols and mono-esterified and di-esterified acylglycerols) at the same time, rendering a useful method for the study of lipase-catalyzed reactions and a wide variety of fats and oils. The present methodology not only separates 18 different lipid classes with a good reproducibility, but it is also able to estimate the relative proportion in which they are found in a broad range of concentrations.

Use of reversed phase HP liquid chromatography to assay conversion of N-acylglycines to primary fatty acid amides by peptidylglycine-alpha-amidating monooxygenase

Primary fatty acid amides (R-CO-NH2) and N-acylglycines (R-CO-NH-CH2-COOH) are classes of compounds that have only recently been isolated and characterized from biological sources. Key questions remain regarding how these lipid amides are produced and degraded in biological systems. Relative to the fatty acids, little has been done to develop methods to separate and quantify the fatty acid amides and N-acylglycines. We describe reversed phase HPLC methods for the separation of C2-C12 primary fatty acid amides and N-acylglycines and also C12-C22 fatty acid amides. Separation within each class occurs primarily on the basis of simple interactions between the acyl chain and the chromatographic stationary phase, but the polar headgroups on these and related fatty acids and N-acylethanolamides modulate the absolute retention in reversed phase mode. We use these methods to measure the enzyme-mediated, two-step conversion of N-octanoylglycine to octanoamide.

Quantification of major lipid classes in human triacylglycerol-rich lipoproteins by high-performance liquid chromatography with evaporative light-scattering detection

Triacylglycerol-rich lipoproteins (TRL), comprising chylomicrons (CM) and very-low-density lipoproteins (VLDL), have been associated with cardiovascular disease. The lipid class content in the remnant particles of these lipoproteins is a determinant for the accumulation of lipids in macrophages and their transformation into foam cells. We have optimized a method for the simultaneous determination of cholesteryl esters (CE), triacylglycerols (TG), free cholesterol (FC), monoacylglycerols (MG), and phospholipids (PL) by HPLC coupled to a light-scattering detector (ELSD). A diol column and a ternary gradient of hexane, 2-propanol, and methanol were applied to CM and VLDL of human origin (n = 10), with excellent precision in terms of repeatability of peak areas and retention times. All peaks were baseline resolved although the resolution of CE and TG was compromised for the sake of simplicity of the solvent gradient. The ELSD response was fitted to second-order equations, with correlation coefficients (r2) higher than 0.999 for a wide range of concentrations (0.25-10 microg of lipid injected). TG were the major lipid class detected in human TRL, accounting for 62% in CM obtained 2 h after the oil intake. In addition we recorded a depletion of TG and CE in CM obtained 2 h after the oil intake of about 60%. We conclude that the method reported here is suitable for a rapid and precise determination of lipid classes in human TRL and, therefore, may be a useful tool for investigations on the atherogenicity of these lipoproteins.

Migration from can coatings: Part 1. A size-exclusion chromatographic method for the simultaneous determination of overall migration and migrating substances below 1000 Da

The Council of Europe Resolution on coatings suggests a limit of 10 mg dm-2 for the sum of substances migrating into food simulants from an internal can coating. The Scientific Committee on Food differentiates the migrants into the substances with a molecular weight below 1000 Da, potentially being of toxicological concern, and the less toxicologically relevant species above 1000 Da. Hitherto, the determination of overall migration was based on a gravimetric method. A new method is described for the simultaneous determination of both overall migration and the migration of substances below 1000 Da based on separation by size exclusion chromatography (SEC) followed by ultraviolet detection (UVD) and evaporative light scattering detection (ELSD). The method is suitable for all volatile extraction media and simulants recommended by the European Union. For statistical comparison of both methods, the slightly modified reference method was validated in-house and extended to an additional gravimetric measurement of the migrants below 1000 Da. For the determination of the overall migration, both methods provided similar reproducibility (validated gravimetry: standard deviation (SD) = 0.16 mg dm-2; SEC-ELSD/UVD: SD = 0.12 mg dm-2) but significantly better results were obtained by the SEC-ELSD/UVD method. For migrating substances below 1000 Da, the gravimetric determination provides a poor sensitivity (limit of detection = 0.35 mg dm-2) compared with the SEC-ELSD/UVD method (limit of detection = 0.04 mg dm-2). The new method offers a lower limit of detection and higher precision as well as being less time consuming and easier to use.