Advantages of online supercritical fluid extraction and chromatography hyphenated to mass spectrometry to analyse plastic additives in laboratory gloves

Plastic additives are introduced in plastic material formulations, along with organic polymers, to offer different properties such as stability, plasticity or color. However, plastic additives may migrate from the plastic material to the content (in case of plastic containers) or to the material in contact with the plastic, like human skin. In the case of plastic medical devices, this migration is of particular interest, as plastic additives may be deleterious to health. In the present paper, we examined the interest of combining supercritical fluid extraction (SFE) to supercritical fluid chromatography (SFC) hyphenated to mass spectrometry (MS) in an online system to characterize plastic additives in laboratory gloves, taken as samples of medical devices. A set of target compounds comprising 18 plasticizers, 4 antioxidants and 2 lubricants was defined and their detectability with MS was examined, where it appeared that electrospray ionization (ESI) provided better detectability than atmospheric pressure chemical ionization (APCI). After examining possible stationary phases with the help of Derringer desirability function, an isocratic chromatographic method (CO2:methanol 95:5) was developed on Shim-pack UC Phenyl column. The extraction method was examined with a 3-level full factorial design of experiments to optimize the extraction temperature (40 °C) and pressure (200 bar). The online SFE-SFC-MS method was compared to offline methods where the samples were extracted with liquid solvents at atmospheric pressure or high pressure then analysed with SFC-MS. In all cases, offline methods showed significant contaminants (like the oleamide lubricant) issuing from laboratory plastic materials as nitrogen drying station, syringes and filters, while the online method allowed a complete elimination of laboratory contaminations. Furthermore, the online method saved time, solvents and laboratory consumables. It will also show that transferring a compressible fluid from a loading loop is favourable to high efficiency, as the resulting chromatographic peaks are much thinner than when transferring a liquid. Compared to injecting liquid heptane, the efficiency increase was 3.4-fold, while compared to injecting liquid methanol (a common practice in SFC), the efficiency increase was 13-fold. Finally, the additive composition of different laboratory gloves was compared.

Food Additives and Evolved Methods of Detection: A Review

Food additives are essential constituents of food products in the modern world. The necessity of food processing went up rapidly as to meet requirements including, imparting desirable properties like preservation, enhancement and regulation of color and taste. The methods of identification and analysis of such substances are crucial. With the advancement of technology, a variety of techniques are emerging for this purpose which have many advantages over the existing conventional ways. This review is on different kinds of additives used in the food industry and few prominent methods for their determination ranging from conventional chromatographic techniques to the recently evolved nano-sensor techniques.

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.

Dissolution-precipitation method concatenated sodium alginate/MOF-derived magnetic multistage pore carbon magnetic solid phase extraction for determination of antioxidants and ultraviolet stabilizers in polylactic acid food contact plastics

Antioxidants and UV stabilizers have some endocrine disrupting effects and liver toxicity. Both types of additives are still widely used in food contact plastics to improve the durability of plastic products. However, efficient and rapid detection of antioxidants and UV stabilizers has been a challenge due to the complexity of the plastic matrix and the low content of antioxidants and UV stabilizers. In this study, a sodium alginate/MOF-derived magnetic multistage pore carbon material (MIL-101(Fe)/SA-CAs) was developed, having the merits of abundant multistage pore structure, large specific surface area, and good magnetic separation properties. Thus, this material was selected as the sorbent for magnetic solid-phase extraction combined with a dissolution-precipitation method for the extraction and purification of antioxidants and UV stabilizers from polylactic acid food contact plastics. The extraction parameters such as sorbent type, sorbent dosage, sample solution pH, ionic strength, sorption time, elution solution type, volume, and time were investigated. Under the optimized conditions, all the analytes determined by UPLC-MS/MS showed good linear range (r > 0.99), detection limit (0.023-3.105 ng g-1), accuracy (70.6-102.3 %), and reproducibility (RSD<9.8 %). Further, the developed method was applied to determine the antioxidants and UV stabilizers in polylactic acid lunch boxes and straws, showing excellent applicability. The results showed that the antioxidants and UV stabilizers were detected in some of the samples, with a maximum detection of antioxidant 1010 at 7297 ng g-1. This study provided a sensitive, efficient, and environmentally friendly method for antioxidants and UV stabilizers in polylactic acid food contact plastics. The ideas for the design of environmentally friendly metal-organic frameworks and biomass composite multifunctional materials would promise in the sample pretreatment field for the emerging contaminants.

Various additive release from microplastics and their toxicity in aquatic environments

Additives may be present in amounts higher than 50% within plastic objects. Additives in plastics can be gradually released from microplastics (MPs) into the aquatic environment during their aging and fragmentation because most of them do not chemically react with the polymers. Some are known to be hazardous substances, which can cause toxicity effects on organisms and pose ecological risks. In this paper, the application of functional additives in MPs and their leaching in the environment are first summarized followed by their release mechanisms including photooxidation, chemical oxidation, biochemical degradation, and physical abrasion. Important factors affecting the additive release from MPs are also reviewed. Generally, smaller particle size, light irradiation, high temperature, dissolved organic matter (DOM) existence and alkaline conditions can promote the release of chemicals from MPs. In addition, the release of additives is also influenced by the polymer's structure, electrolyte types, as well as salinity. These additives may transfer into the organisms after ingestion and disrupt various biological processes, leading to developmental malformations and toxicity in offspring. Nonetheless, challenges on the toxicity of chemicals in MPs remain hindering the risk assessment on human health from MPs in the environment. Future research is suggested to strengthen research on the leaching experiment in the actual environment, develop more techniques and analysis methods to identify leaching products, and evaluate the toxicity effects of additives from MPs based on more model organisms. The work gives a comprehensive overview of current process for MP additive release in natural waters, summarizes their toxicity effects on organisms, and provides recommendations for future research.

NiGA MOF-based dispersive micro solid phase extraction coupled to temperature-assisted evaporation using low boiling point solvents for the extraction and preconcentration of butylated hydroxytoluene and some phthalate and adipate esters

The first-ever attempt to apply nickel gallic acid metal-organic framework (NiGA MOF) in analytical method development was done in this research by the extraction of some plasticizers from aqueous media. The greenness of the method is owing to the use of gallic acid and nickel as safe reagents and water as the safest solvent. Low boiling point solvents were applied as desorption solvents that underwent temperature-assisted evaporation in the preconcentration step. Performing the evaporation using a low-temperature water bath for a short period of time streamlines the preconcentration section. Into the solution of interest enriched with sodium sulfate, a mg amount of NiGA MOF was added alongside vortexing to extract the analytes. Following centrifugation and discarding the supernatant, a μL level of diethyl ether was added onto the analyte-loaded NiGA MOF particles and vortexed. The analyte-enriched diethyl ether phase was transferred into a conical bottom glass test tube and located in a water bath set at the temperature of 35 °C under a laboratory hood. After the evaporation, a μL level of 1,2-dibromoethane was added to the test tube and vortexed to dissolve the analytes from the inner perimeter of the tube. One microliter of the organic phase was injected into a gas chromatograph equipped with flame ionization detection. Appreciable extraction recoveries (61-98%), high enrichment factors (305-490), low limits of detection (0.80-1.74 μg L-1) and quantification (2.64-5.74 μg L-1), and wide linear ranges (5.74-1000 μg L-1) were obtained at the optimum conditions.

Occurrence, Fate, Human Exposure, and Toxicity of Commercial Photoinitiators

Photoinitiators (PIs) are a family of anthropogenic chemicals used in polymerization systems that generate active substances to initiate polymerization reactions under certain radiations. Although polymerization is considered a green method, its wide application in various commercial products, such as UV-curable inks, paints, and varnishes, has led to ubiquitous environmental issues caused by PIs. In this study, we present an overview of the current knowledge on the environmental occurrence, human exposure, and toxicity of PIs and provide suggestions for future research based on numerous available studies. The residual concentrations of PIs in commercial products, such as food packaging materials, are at microgram per gram levels. The migration of PIs from food packaging materials to foodstuffs has been confirmed by more than 100 reports of food contamination caused by PIs. Furthermore, more than 20 PIs have been detected in water, sediment, sewage sludge, and indoor dust collected from Asia, the United States, and Europe. Human internal exposure was also confirmed by the detection of PIs in serum. In addition, PIs were present in human breast milk, indicating that breastfeeding is an exposure pathway for infants. Among the most available studies, benzophenone is the dominant congener detected in the environment and humans. Toxicity studies of PIs reveal multiple toxic end points, such as carcinogenicity and endocrine-disrupting effects. Future investigations should focus on synergistic/antagonistic toxicity effects caused by PIs coexposure and metabolism/transformation pathways of newly identified PIs. Furthermore, future research should aim to develop "greener" PIs with high efficiency, low migration, and low toxicity.

Insight into chemical features of migrated additives from plastics and associated risks to estuarine ecosystem

Distinct hydrodynamic conditions created a hotspot of plastic and associated additive pollution within estuaries, which is of considerable scientific interest. However, the effects of specific estuarine weathering (severe mechanical wear, constant turbulence, and strong ultraviolet radiation) on migration of additives remain unclear. Therefore, we investigated the release of migrated plastic additives (MPAs) from three representative plastics, namely floating foam, fishing nets, and packaging bags, under simulated estuarine conditions. Sixty-seven MPAs leached out under the wave scenario, greater than those under the ultraviolet radiation (62) and shoal (40) scenarios. We detected forty MPAs in the plastic bag leachates, whereas fewer MPAs were released from the foam and nets. Several MPAs were peculiar to specific plastics, e.g., antistatic and curing agents in the bag and foam leachates, respectively. Particularly, a suite of nonionic surfactants, octylphenol polyethoxylates (OPEO_n), exhibited outstanding responses in the packaging bag leachates and had elevated toxic potential. OPEO_n significantly inhibited the hatching of zebrafish and caused cardiovascular system disorder and morphological distortions even at environmentally relevant concentrations as in estuaries. Collectively, the leaching of MPAs was significantly enhanced by wave actions, and the plastic leachates, particularly those of plastic bags, can cause detrimental risks to the estuarine ecosystem.

Valoration of the Synthetic Antioxidant Tris-(Diterbutyl-Phenol)-Phosphite (Irgafos P-168) from Industrial Wastewater and Application in Polypropylene Matrices to Minimize Its Thermal Degradation

Industrial wastewater from petrochemical processes is an essential source of the synthetic phenolic phosphite antioxidant (Irgafos P-168), which negatively affects the environment. For the determination and analysis of Irgafos P-168, DSC, HPLC-MS, and FTIR methodologies were used. Solid phase extraction (SPE) proved to be the best technique for extracting Irgafos from wastewater. HPLC-MS and SPE determined the repeatability, reproducibility, and linearity of the method and the SPE of the standards and samples. The relative standard deviations, errors, and correlation coefficients for the repeatability and reproducibility of the calibration curves were less than 4.4% and 4.2% and greater than 0.99955, respectively. The analysis of variance (ANOVA), using the Fisher method with confidence in 95% of the data, did not reveal significant differences between the mentioned parameters. The removal of the antioxidant from the wastewater by SPE showed recovery percentages higher than 91.03%, and the chemical characterization of this antioxidant by FTIR spectroscopy, DSC, TGA, and MS showed it to be structurally the same as the Irgafos P-168 molecule. The recovered Irgafos was added to the polypropylene matrix, significantly improving its oxidation times. An OIT analysis, performed using DSC, showed that the recovered Irgafos-blended polypropylene (PP) demonstrated oxidative degradation at 8 min. With the addition of the Irgafos, the oxidation time was 13 min. This increases the polypropylene's useful life and minimizes the environmental impact of the wastewater.

A generic scenario analysis of end-of-life plastic management: Chemical additives

Plastic growing demand and the increment in global plastics production have raised the number of spent plastics, out of which over 90% are either landfilled or incinerated. Both methods for handling spent plastics are susceptible to releasing toxic substances, damaging air, water, soil, organisms, and public health. Improvements to the existing infrastructure for plastics management are needed to limit chemical additive release and exposure resulting from the end-of-life (EoL) stage. This article analyzes the current plastic waste management infrastructure and identifies chemical additive releases through a material flow analysis. Additionally, we performed a facility-level generic scenario analysis of the current U.S. EoL stage of plastic additives to track and estimate their potential migration, releases, and occupational exposure. Potential scenarios were analyzed through sensitivity analysis to examine the merit of increasing recycling rates, using chemical recycling, and implementing additive extraction post-recycling. Our analyses identified that the current state of plastic EoL management possesses high mass flow intensity toward incineration and landfilling. Although maximizing the plastic recycling rate is a reasonably straightforward goal for enhancing material circularity, the conventional mechanical recycling method requires improvement because major chemical additive release and contamination routes act as obstacles to achieving high-quality plastics for future reuse and should be mitigated through chemical recycling and additive extraction. The potential hazards and risks identified in this research create an opportunity to design a safer closed-loop plastic recycling infrastructure to handle additives strategically and support sustainable materials management efforts to transform the US plastic economy from linear to circular.

Development of a SPE-HPLC-PDA Method for the Quantification of Phthalates in Bottled Water and Their Gene Expression Modulation in a Human Intestinal Cell Model

Phthalates are ubiquitous pollutants that are currently classified as endocrine disruptor chemicals causing serious health problems. As contaminants of food and beverages, they come into contact with the epithelium of the intestinal tract. In this work, a SPE-HPLC-PDA method for the determination of phthalates in water from plastic bottles was developed and validated according to the food and drug administration (FDA) guidelines. A chromatographic separation was achieved using a mobile phase consisting of ammonium acetate buffer 10 mM pH 5 (line A) and a mixture of methanol and iso-propanol (50:50 v/v, line B) using gradient elution. Several SPE cartridges and different pH values were investigated for this study, evaluating their performance as a function of recovery. Among these parameters, pH 5 combined with the SPE sep pack C18 cartridge showed the best performance. Finally, the proposed method was applied to the analysis of real samples, which confirmed the presence of phthalates. A colonic epithelial cell model was used to evaluate the effects of these phthalates at the concentrations found in water from plastic bottles. In cells exposed to phthalates, the increased expression of factors, which control the signaling pathways necessary for intestinal epithelium homeostasis, inflammatory response, and stress was detected. The proposed method falls fully within the limits imposed by the guidelines with precision (RSD%) below 7.1% and accuracy (BIAS%) within −4.2 and +6.1.

Sodium alginate and pectin estimation in raft forming pharmaceuticals by high performance liquid chromatography method

The high performance liquid chromatographic (HPLC) method was developed for the combined estimation of sodium alginate and pectin in raft forming pharmaceuticals on C18 column ZORBAX ODS (1.5 cm × 4.6 mm, 5 μm) with UV detection at 378 nm. The assay condition comprised of phosphate buffer pH 7.4 and methanol 60:40% v/v at a flow rate of 1.25 mL/min. The separation of sodium alginate and pectin with good resolution and a retention time less than 8 min was attained. The method was linear over a range of 200–800 μg/mL of sodium alginate and pectin. The regression values obtained from linearity curve of sodium alginate and pectin were 0.9993 and 0.9991, respectively. The retention time of sodium alginate and pectin was 3.931 and 7.470 min, respectively. The percent recovery of sodium alginate and pectin ranged from 94.2–98.5% and 92.1–98.4% respectively. The limit of detection (LOD) and limit of quantification (LOQ) of sodium alginate were found to be 2.443 and 3.129 μg/mL and the LOD and LOQ of pectin were 3.126 and 3.785 μg/mL, respectively. The resolution of sodium alginate and pectin was found in the range of 1.03–1.89 and 1.10–1.91, respectively. This method has been successfully applied to analyze the concentrations of sodium alginate and pectin in raft forming drug delivery systems.

Photo aging and fragmentation of polypropylene food packaging materials in artificial seawater

Plastic litters in marine environment usually contain varied types and contents of additives that can significantly affect the photochemical aging and fragmentation process of microplastics (MPs). This study investigated the photo aging process of two common polypropylene (PP) food packaging materials (i.e., meal box and tea cup) in artificial seawater within 12 d of ultraviolet (UV) irradiation. Results revealed that the aging of both plastic materials were critically inhibited compared with pure PP, indicating that PP food packaging materials in natural seawater may share longer aging time than pure ones. GC-MS analysis revealed that antioxidant Irgafos 168 (tris (2,4-di-tert-butylphenyl) phosphite) was the dominant additive in these plastic materials. Photo reaction between Irgafos 168 and hydroperoxide species on the surface of MPs to prevent the formation of hydroxyl radical was the possible mechanism for the inhibiting effects. After antioxidant was exhausted, its photo degradation products could become the dominant contributor to influence the aging process of MPs. This is the first work exploring the role of antioxidant on the aging process of PP MPs in simulated ocean environment. The findings could be of great help for unraveling the effect of antioxidants on the aging-related environmental risk of hydrocarbon plastics in ocean environment.

Migration regularity of phthalates in polyethylene wrap film of food packaging

As a kind of polymer material additive, phthalic acid esters (PAEs) are widely used in food industry. However, PAEs are environmental endocrine disruptors with reproductive toxicity and teratogenic carcinogenicity, which are difficult to be degraded in the natural environment. In this paper, gas chromatography-mass spectrometer (GC-MS) methods for PAEs in polyethylene wrap film were optimized. For diisobutyl phthalate (DIBP) and dibutyl phthalate (DBP) that were mainly detected, the method had a good linearity in 1 to 500 ng/g. Then, we confirmed that the migration of DIBP and DBP from polyethylene wrap film increased with time and temperature. It is found that the migration law in different food simulations well followed the migration dynamics first-level model. The rate constant K₁ and initial release rate V₀ are inversely proportional to the polarity of the simulated liquid. We hope that this study can serve as a valuable reference for further research on the migration of food packing materials. PRACTICAL APPLICATION: In this paper, we present a simple example of applying migration model to evaluate the migration behaviors of PAEs in food packaging materials along with their hazardous properties. It can serve as a valuable reference for further research on the migration of food packing materials.

Occurrence of plastic additives in outdoor air particulate matters from two industrial parks of Tarragona, Spain: Human inhalation intake risk assessment

Plastic additives include several kinds of chemicals that are added to the polymer matrix to improve the final product quality and prevent deterioration effects. They are used in a large quantity of materials, so their presence in the environment is expected. This study has developed and validated a method based on gas chromatography-mass spectrometry after pressurised liquid extraction to determine sixteen plastic additives including UV-stabilizers, aromatic and phenolic antioxidants and some of their degradation products in particulate matter (PM₁₀) from outdoor air. Apparent recoveries were above 85% for most of compounds and low detection limits (pg m^-3) were achieved. This is the first study to determine these types of contaminant in the PM₁₀ of outdoor air from two locations surrounded by different industries. Various compounds were found in almost all samples; BHT, BHT-Q, 2,4-DTBP, BHT-CHO, UV320, UV328, Irgafos168 and Iragonx1076, with concentrations ranging from < MQL to 2860 pg m^-3. Estimated daily intakes (EDIs) via ambient inhalation were calculated for each polymer additive and for different subpopulation groups classified by age. Two possible exposure scenarios (low, based on geometric mean, and high, 95th percentile) were simulated, and 0.51 ng kg_bw^-1 day^-1 was the EDI in the worst case scenario for children.

tert-Butylphenolic Derivatives from Paenibacillus odorifer-A Case of Bioconversion

Two compounds (1) and (2) containing tert-butylphenol groups were, for the first time, produced during the culture of Paenibacillus odorifer, a bacterial strain associated with the crustose lichen, Rhizocarpon geographicum. Their entire structures were identified by one-dimensional (1D) and two-dimensional (2D) NMR and high-resolution electrospray ionisation mass spectrometry (HRESIMS) spectroscopic analyses. Among them, Compound 1 exhibited significant cytotoxicity against B16 murine melanoma and HaCaT human keratinocyte cell lines with micromolar half maximal inhibitory concentration (IC₅₀) values. Furthermore, after supplementation studies, a putative biosynthesis pathway was proposed for Compound 1 throughout a bioconversion by this bacterial strain of butylated hydroxyanisole (BHA), an antioxidant polymer additive.

Study of the Migration of Stabilizer and Plasticizer from Polyethylene Terephthalate into Food Simulants

This study investigates the determination and migration of stabilizers and plasticizers from polyethylene terephthalate (PET). Two methods [ultrasonic extraction with dichloromethane or methanol and total dissolution with phenol/tetrachloroethane (m:m/1:1)] for pre-concentration of additives in PET material were performed. The diffusion of these additives from PET was evaluated by immersing in deionized water, acetic acid 3% (w/v), ethanol 20% (v/v), ethanol 50% (v/v) and isooctane at 20, 40, 55 and 70°C, respectively. The amount of additives in PET and food simulants was quantified by high-performance liquid chromatography-photodiode array detector (HPLC-PDA). The optimized HPLC method showed high correlation coefficients (R ≥ 0.9993), good precision, accuracy and reproducibility. Experimental diffusion coefficients (DP) were calculated according to a mathematical model based on Fick's second law, and the DP values of considered compounds ranged from 9.8 × 10(-15) to 1.4 × 10(-8) cm(2) s(-1) The experimental DP values were also compared with that predicted by currently used diffusion models. In addition, the effect of temperature on the diffusion rate was assessed. The effect of temperature on the diffusion coefficients followed an Arrhenius-type model with active energies ranged from 40.4 to 113.8 kJ mol(-1) for the target compounds.

Screening of additives in plastics with high resolution time-of-flight mass spectrometry and different ionization sources: direct probe injection (DIP)-APCI, LC-APCI, and LC-ion booster ESI

Plastics are complex mixtures consisting of a polymer and additives with different physico-chemical properties. We developed a broad screening method to elucidate the nature of compounds present in plastics used in electrical/electronic equipment commonly found at homes (e.g., electrical adaptors, computer casings, heaters). The analysis was done by (a) solvent extraction followed by liquid chromatography coupled to high accuracy/resolution time-of-flight mass spectrometry (TOFMS) with different ionization sources or (b) direct analysis of the solid by ambient mass spectrometry high accuracy/resolution TOFMS. The different ionization methods showed different selectivity and sensitivity for the different compound classes and were complementary. A variety of antioxidants, phthalates, UV filters, and flame retardants were found in most samples. Furthermore, some recently reported impurities or degradation products derived from flame retardants were identified, such as hydroxylated triphenyl phosphate and tetrabromobisphenol A monoglycidyl ether.

Graphical abstract

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.