DETERMINATION OF 7 ANTIOXIDANTS, 8 ULTRAVIOLET ABSORBENTS, AND 2 FIRE RETARDANTS IN PLASTIC FOOD PACKAGE BY ULTRASONIC EXTRACTION AND ULTRA PERFORMANCE LIQUID CHROMATOGRAPHY

Amine Switchable Hydrophilic Solvent Vortex-Assisted Homogeneous Liquid-Liquid Microextraction and GC-MS for the Enrichment and Determination of 2, 6-DIPA Additive in Biodegradable Film

2, 6-diisopropylaniline (2, 6-DIPA) is a crucial non-intentionally organic additive that allows the assessment of the production processes, formulation qualities, and performance variations in biodegradable mulching film. Moreover, its release into the environment may have certain effects on human health. Hence, this study developed simultaneous heating hydrolysis-extraction and amine switchable hydrophilic solvent vortex-assisted homogeneous liquid-liquid microextraction for the gas chromatography-mass spectrometry analysis of the 2, 6-DIPA additive and its corresponding isocyanates in poly(butylene adipate-co-terephthalate) (PBAT) biodegradable agricultural mulching films. The heating hydrolysis-extraction conditions and factors influencing the efficiency of homogeneous liquid-liquid microextraction, such as the type and volume of amine, homogeneous-phase and phase separation transition pH, and extraction time were investigated and optimized. The optimum heating hydrolysis-extraction conditions were found to be a H2SO4 concentration of 2.5 M, heating temperature of 87.8 °C, and hydrolysis-extraction time of 3.0 h. As a switchable hydrophilic solvent, dipropylamine does not require a dispersant. Vortex assistance is helpful to speed up the extraction. Under the optimum experimental conditions, this method exhibits a better linearity (0.0144~7.200 μg mL-1 with R = 0.9986), low limit of detection and quantification (0.0033 μg g-1 and 0.0103 μg g-1), high extraction recovery (92.5~105.4%), desirable intra- and inter-day precision (relative standard deviation less than 4.1% and 4.7%), and high enrichment factor (90.9). Finally, this method was successfully applied to detect the content of the additive 2, 6-DIPA in PBAT biodegradable agricultural mulching films, thus facilitating production process monitoring or safety assessments.

The Mechanisms of Plastic Food-Packaging Monomers' Migration into Food Matrix and the Implications on Human Health

The development of packaging technology has become a crucial part of the food industry in today's modern societies, which are characterized by technological advancements, industrialization, densely populated cities, and scientific advancements that have increased food production over the past 50 years despite the lack of agricultural land. Various types of food-packaging materials are utilized, with plastic being the most versatile. However, there are certain concerns with regards to the usage of plastic packaging because of unreacted monomers' potential migration from the polymer packaging to the food. The magnitude of monomer migration depends on numerous aspects, including the monomer chemistry, type of plastic packaging, physical-chemical parameters such as the temperature and pH, and food chemistry. The major concern for the presence of packaging monomers in food is that some monomers are endocrine-disrupting compounds (EDCs) with a capability to interfere with the functioning of vital hormonal systems in the human body. For this reason, different countries have resolved to enforce guidelines and regulations for packaging monomers in food. Additionally, many countries have introduced migration testing procedures and safe limits for packaging monomer migration into food. However, to date, several research studies have reported levels of monomer migration above the set migration limits due to leaching from the food-packaging materials into the food. This raises concerns regarding possible health effects on consumers. This paper provides a critical review on plastic food-contact materials' monomer migration, including that from biodegradable plastic packaging, the monomer migration mechanisms, the monomer migration chemistry, the key factors that affect the migration process, and the associated potential EDC human health risks linked to monomers' presence in food. The aim is to contribute to the existing knowledge and understanding of plastic food-packaging monomer migration.

Determination of 18 photoinitiators in food paper packaging materials by FastPrep-based extraction combined with GC-MS

Extraction of photoinitiators (PIs) from food paper packages is difficult since they normally hide inside multiple ink layers. A one-step FastPrep-based extraction in combination with GC-MS was developed to simultaneously measure 18 PIs in food paper packaging materials. FastPrep-based extraction enabled direct and efficient release of PIs from raw paperboard in a minute without additional procedures. It was simple, high-throughput, consuming less solvent and not requiring heat or radiation. GC-MS using selected ion monitoring provided identification of PIs with high selectivity. The LODs and LOQs for 18 PIs ranged from 0.060 to 0.614 mg/kg, and 0.197-2.027 mg/kg, respectively. The method was successfully applied for various real samples, and the spiked recoveries using different real sample matrices ranged from 93.3% to 110.1%. The developed method can thus be used for the quality control of PI residues in paper packaging materials of food products.

A fast SALLE GC-MS/MS multi-analyte method for the determination of 75 food packaging substances in food simulants

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/H₂O 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.

Development and validation of a multi-analyte GC-MS method for the determination of 84 substances from plastic food contact materials

Chemical substances shall not migrate from food contact materials (FCM) at levels that are potentially harmful for the consumers. Each of the current analytical methods applied to verify the migration of substances from FCM covers only one or few substances. There is a very limited number of publications on the development of analytical methods allowing the simultaneous determination of several classes of FCM substances, and almost none of them reported methods entirely dedicated to the ones in the positive list of Commission Regulation (EU) No. 10/2011 for plastic FCMs. Therefore, a simple, sensitive and reliable multi-analyte method was developed for the analysis of FCM substances in food simulants. It employs an optimised liquid-liquid extraction with dichloromethane as extraction solvent in the presence of 10% m/v NaCl, followed by quantitative analysis with gas chromatography coupled to mass spectrometry (GC-MS). A combination of total ion chromatograms (TICs) and extracted ion chromatograms (EICs) was used. The optimisation and validation of the method have been carried out according to current international guidelines. Adequate sensitivity was demonstrated in the selected concentration ranges for most of the analytes, with limits of quantification (LOQs) at least three times lower than the legislative limit, when existing. The results showed that the method is sufficiently accurate for the majority of substances, with recoveries between 70 and 115% and relative standard deviations (RSDs) smaller than 20% at three concentration levels. The method was applied to the analysis of some FCM multilayers. The method allows, for the first time, the simultaneous quantification of 84 FCM substances in two of the official food simulants (A and C) at levels of a few ng g⁻¹.

Challenges and opportunities of solvent-based additive extraction methods for plastic recycling

Additives are ubiquitously used in plastics to improve their functionality. However, they are not always desirable in their 'second life' and are a major bottleneck for chemical recycling. Although research on extraction techniques for efficient removal of additives is increasing, it resembles much like uncharted territory due to the broad variety of additives, plastics and removal techniques. Today solvent-based additive extraction techniques, solid-liquid extraction and dissolution-precipitation, are considered to be the most promising techniques to remove additives. This review focuses on the assessment of these techniques by making a link between literature and physicochemical principles such as diffusion and Hansen solubility theory. From a technical point of view, dissolution-precipitation is preferred to remove a broad spectrum of additives because diffusion limitations affect the solid-liquid extraction recoveries. Novel techniques such as accelerated solvent extraction (ASE) are promising for finding the balance between these two processes. Because of limited studies on the economic and environmental feasibility of extraction methods, this review also includes a basic economic and environmental assessment of two extreme cases for the extraction of additives. According to this assessment, the feasibility of additives removal depends strongly on the type of additive and plastic and also on the extraction conditions. In the best-case scenario at least 70% of solvent recovery is required to extract plasticizers from polyvinyl chloride (PVC) via dissolution-precipitation with tetrahydrofuran (THF), while solid-liquid extraction of phenolic antioxidants and a fatty acid amide slip agents from polypropylene (PP) with dichloromethane (DCM) can be economically viable even without intensive solvent recovery.

Identification and quantification of unknown antioxidants in plastic materials by ultrasonic extraction and ultra-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry

Mass spectrometry has been applied to the targeted analysis of commonly used additives (such as Irganox 1010, Irganox 1076, Irgafos 168, etc.) in plastic materials, but a fast and straightforward method for the non-targeted identification and quantification of unusual or potentially new antioxidant additives is still unavailable. In this study, a novel and simple method for the identification and quantification of unknown antioxidant additives in plastic food packaging using ultrasonic extraction and ultra-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry has been developed. A method for the Irganox series analyzed here has not been reported previously. Unknown antioxidant additives have been identified by accurate m/z determination, MS(2) fragments and comparison with synthesized standards. The mass fragmentation patterns and structural assignments of these antioxidants have been studied. Parameters affecting the efficiency of the process, such as extraction solvents, extraction volume, extraction time and chromatographic conditions, have been studied and optimized. Ultrasonic extraction of plastic materials (40 mg) with dichloromethane (0.5 mL) at 25 °C was applied as optimal. Limits of detection of the target additives ranged from 0.5 ng g(-1) to 1.5 ng g(-1), and the detection was linear over the range studied (0.01-1.5 µg mg(-1), r(2)>0.99). The accuracy of the method has been tested by relative recovery experiments with spiked samples, with results ranging from 94.3% to 104.8%, and the precision (relative standard deviation) was within 11.0% (n=3). Finally, the method has been successfully applied to the determination of antioxidants in several real plastic samples.