Identification and quantification of plastic additives using pyrolysis-GC/MS: A review

Sequential combination of micro-FTIR imaging spectroscopy and pyrolysis-GC/MS for microplastic quantification. Application to river sediments

Several studies have focused on quantifying microplastics (MP) in the environment using μ-FTIR and Py-GC/MS, the most common analytical methods. However, their application to complex matrices like sediments is affected by interferences specific to each method. In this study, we developed a protocol combining μ-FTIR and Py-GC/MS for sequential analysis of MP (10-500 μm) in 16 river sediment samples, targeting PE, PP, and PS polymers. Mass concentrations were estimated from the particle volume in μ-FTIR and measured directly by Py-GC/MS using internal calibration. Results show consistency between the two methods across different sites, with variability of two orders of magnitude in concentration ranges from 0.3 to 50 items g-1 and 0.2 to 17 μg g-1 for μ-FTIR, and 0.8 to 21 μg g-1 for Py-GC/MS. Replicate analyses (2 to 6 per site) revealed that intra-site variability was mainly influenced by sample preparation and, to a lesser extent, by the measurement technique. While estimated and measured concentrations were similar, discrepancies were observed in polymer proportions: PP predominated in μ-FTIR, while PS was more prevalent in Py-GC/MS. These differences are explained by the specific limitations of each method, especially the limited detection of synthetic fibres and tyre or road abrasion particles by μ-FTIR, which are detected as MP by Py-GC/MS. This comparative study provides recommendations for evaluating compatibility between studies using either technique and offers guidelines for selecting the most appropriate method based on research interests.

Quantification of Brominated Flame Retardants in Synthetic Polymers via Direct Mass Spectrometric Analysis

Brominated flame retardants (BFRs) are persistent organic pollutants commonly encountered in plastics. Herein, we report on the quantification of BFRs directly from plastic samples via direct insertion probe mass spectrometry (DIP-MS). The study was conducted using model polymer samples comprising either acrylonitrile butadiene styrene copolymer (ABS) or high impact polystyrene (HIPS) and a BFR, namely decabromodiphenyl ether (decaBDE), hexabromocyclododecane (HBCD), or tetrabromobisphenol A (TBBPA). DIP-MS enabled direct quantification of decaBDE and TBBPA from both ABS and HIPS matrices. A linear correlation between BFR signal intensity and bromine (Br) content of the samples, as determined by X-ray fluorescence, was established over a Br concentration range of 0-7 wt %, or even higher. While DIP-MS showed potential for HBCD analysis as well, its effectiveness for quantitative HBCD determination remains partly uncertain due to the observed reactivity of HBCD during sample preparation. The detection limits for all studied BFRs were below 500 mg Br/kg. Additionally, the study shed light on matrix effects related to additive analysis by DIP-MS, revealing that the polymer and other additives can affect BFR volatilization and reactivity. Overall, DIP-MS demonstrated significant potential for the rapid quantification of BFRs from plastic samples with minimal sample preparation, which is imperative for promoting more efficient plastic recycling.

Blood and cloacal microbiome profile of captive green turtles (Chelonia mydas) and hawksbill turtles (Eretmochelys imbricata): Water quality and conservation implications

In this study, we studied the environment factors such as plastics and heavy metals affecting the blood and cloacal microbiome of green (Chelonia mydas) and hawksbill (Eretmochelys imbricata) in captivity. By non-metric multidimensional scaling analysis, data has shown that the environment factors (p = 0.02), rather than species differences (p = 0.06), significantly influenced the composition of the cloacal microbiota of green and hawksbill turtles. The cloacal microbiota of both captive green and hawksbill turtles was dominated by several similar dominant phyla at differential abundance. Green turtles' cloacal microbiome was made up of 46% of Proteobacteria, 31% of Bacteroidota, 11% of Campylobacterota and 4% of Firmicutes, while the hawksbill turtles' cloacal microbiome was made up of 33% of Bacteroidota, 18% of Firmicutes, 17% of Proteobacteria, and 2% of Campylobacterota. Water conductivity, salinity, microplastic polymers (polycarbonate, polyethylene terephthalate, polystyrene), and copper are positively associated (p < 0.05) with blood urea nitrogen. Hematocrit and hemoglobin were found also negatively correlated (p < 0.05) with water pH, polyethylene terephthalate, iron, lead and zinc. The correlations established in this study shed light on the intricate interplay between water quality and the physiological responses of sea turtles. Recognizing these relationships is pivotal for monitoring and preserving the well-being of sea turtles in their natural habitats.

Photodegradation Controls of Potential Toxicity of Secondary Sunscreen-Derived Microplastics and Associated Leachates

The escalating environmental concern over secondary microplastics (SMPs) stems from their physicochemical evolution from primary microplastics (PMPs), yet the contribution of varying physicochemical transformations to the ultimate environmental risks remains unknown. In this study, a photomechanical degradation process was employed to convert the primary sunscreen-derived microplastics (SDMPs) into secondary SDMPs. While mechanical degradation caused physical fragmentation, photodegradation induced both physical and chemical alterations, introducing surface oxidation, chemical bond scission, and cross-linking to the secondary SDMPs. Employing a combination of alkaline digestion and pyrolysis GC-MS techniques, it was observed that both physical fragmentation and photooxidation led to heightened intracellular sequestration of MPs. Although the bioaccumulated SDMPs could be indicated by the enlarged lysosomes and fragmented mitochondria, toxicity of secondary SDMPs at the cellular level was primarily driven by chemical transformations post-photodegradation. A nontargeted analysis employing high-resolution mass spectrometry identified 46 plastic-associated compounds in the leachate, with photodegradation-induced chemical transformations playing a crucial role in the dissociation of hydrophobic additives and oxidative conversion of leached compounds. The toxicity of the leachate was exacerbated by photodegradation, with mitochondrial fragmentation serving as the primary subcellular biomarker, indicative of leachate toxicity. This study elucidates the pivotal role of photodegradation in augmenting the cytotoxicity of secondary SDMPs, shedding light on the intricate interplay between physicochemical transformations and environmental risks.

A practical approach to quantitative analytical surface-enhanced Raman spectroscopy

Many of the features of SERS, such as its high sensitivity, molecular specificity and speed of analysis make it attractive as an analytical technique. However, SERS currently remains a specialist technique which has not yet entered the mainstream of analytical chemistry. Therefore, this review draws out the underlying principles for analytical SERS and provides practical tips and tricks for SERS quantitation. The aim is to show the readers how to rationally design their SERS experiments to improve quantitation performance. We begin by introducing the three core components in SERS analysis: (1) the enhancing substrate material, (2) the Raman instrument and (3) the processed data that is used to establish a calibration curve. This is followed by discussion of the analytical figures of merit relevant to SERS. In the following sections each of the three essential components in SERS quantitation and how they affect the quality of the analysis are described in more detail using examples from the literature. Finally, we highlight the current challenges in applying SERS to the analysis of complex real-life samples and briefly introduce the state-of-the-art developments on multifunctional substrates, digital SERS and AI-assisted data processing, which will help SERS rise to the challenge of moving out into routine real-world analysis.

A review of airborne micro- and nano-plastics: Sampling methods, analytical techniques, and exposure risks

Atmospheric Micro- and nano-plastics (MNPs) can be easily inhaled and ingested by humans and have become a global health concern. With the development of instruments and techniques, an increasing number of sampling and analytical methods have been applied to study airborne MNPs. Active samplers and passive collectors are used to collect suspended aerosols and atmospheric depositions. Microscopes and scanning electron microscopy (SEM) have been used to physically identify the MNPs, while Fourier transform infrared (FTIR), Raman spectroscopy, and Pyrolysis gas chromatography-mass spectrometry (Py-GC/MS) are used to identify the polymer compositions of the MNPs. However, the diversity of methods and strategies has greatly limited our ability to compare results and assess exposure risks. In this review, we extracted data from PubMed, Embase, and Scopus from 2018 to 2024 that reported sampling methods, analytical techniques, and abundance/deposition of airborne MNPs. Through a systematic review of the included 140 articles, we emphasized the advantages and limitations of different methods for collecting and analyzing airborne MNPs. In addition, we provided an in-depth analysis of the performance of specific methods across different airborne environments. Furthermore, the current knowledge regarding the abundance, deposition, exposure risks of airborne MNPs, and exposure risk assessment models has been discussed. Finally, we provide concrete recommendations for standardization of methods. This review identified knowledge gaps and recommended future research directions for exposure assessment of airborne MNPs.

Autopsy of a Hemodialysis Machine: Potential for Recycling at the End of the Life Cycle

Key Points

Background

Hemodialysis contributes significantly to health care's carbon footprint. Worldwide, approximately 100,000 dialysis machines end their life cycle each year. Our aim was to analyze the composition and potential for recyclability of two dialysis machines, from the two companies with the largest market share, which had met their end-of-use terms (10–12 years of use according to French regulations).

Methods

One 5008 CorDiax (Fresenius Medical Care AG) and one Artis/Evosys (Gambro AB) were dismantled, and each piece was analyzed in terms of weight and principal components (plastic, metal, mixed materials, and electronic components). The time needed to disassemble the machine was recorded. Samples of 15 plastic elements were further studied using Fourier-transform infrared spectroscopy. The results were compared with the data provided by the manufacturers.

Results

The dismantled hemodialysis machines weighed 125.0 kg and 141.4 kg; plastic, metal, mixed materials, and electronic components accounted for 28%, 15%, 51%, and 6% of the first machine's weight and 28%, 19%, 40%, and 13% of the second's, respectively. The time needed to manually disassemble a dialysis machine into macro elements was around 12 hours. Dismantling into single materials was evaluated as needing at least 1 workweek (35 hours). The plastic elements were mostly a mixture of resins (petroleum-based material used to manufacture plastics), which makes their recycling potential negligible.

Conclusions

This study demonstrates that hemodialysis machines contribute to waste production at the end of their life cycle, with low recycling potential, and underlines the need to rethink their design in a cradle-to-cradle perspective.

Towards realism in hazard assessment of plastic and rubber leachates - Methodological considerations

While plastic chemicals are key drivers of observed effects to aquatic species, there remains a lack of standardized and fit-for-purpose approaches for experimentally deconvoluting the effects of plastic chemicals from particle effects. This study investigated differences in chemical composition determined using two different organic solvents for extractions (dichloromethane-ethyl acetate, methanol) and by thermal desorption applied to 51 thermoplastic and elastomer products. The composition of natural water leachates of four select elastomers was also investigated. The number of chemical features in each material varied according to the extraction method, with solvent extracts exhibiting the most chemicals, and only 19 compounds commonly identified by all three methods. The number of chemical features in leachates was generally similar to the corresponding chemical extracts, but strong differences in relative composition were detected. While turbulence had minimal impact on leachate composition, particle loading strongly influenced leachate composition, temperature and salinity influenced the leachate concentration for some chemicals, and leaching time depended upon chemical mobility. Leachate composition cannot be readily predicted from particle characterization and multiple parameters are drivers of compositional variance in aquatic leachates. Recommendations for performing leaching studies that are relevant for hazard characterization in a realistic aquatic environment risk assessment scenario are suggested, with a particular focus on particle loading.

Chemical toxicity of leachates from synthetic and natural-based spat collectors on the embryo-larval development of the pearl oyster, Pinctada margaritifera

In French Polynesia, the pearl farming industry relies entirely on collecting natural spat using a shade-mesh collector, which is reported to contribute to both plastic pollution and the release of toxic chemicals. With the aim of identifying more environment-friendly collectors, this study investigates the chemical toxicity of shade-mesh (SM) and alternative materials, including reusable plates (P), a newly developed biomaterial (BioM) and Coconut coir geotextile (Coco), on the embryo-larval development of Pinctada margaritifera. Embryos were exposed during 48 h to four concentrations (0, 0.1, 10 and 100 g L-1) of leachates produced from materials. Chemical screening of raw materials and leachates was performed to assess potential relationships with the toxicity observed on D-larvae development. Compared to the other tested materials, results demonstrated lower levels of chemical pollutants in BioM and no toxic effects of its leachates at 10 g L-1. No toxicity was observed at the lowest tested concentration (0.1 g L-1). These findings offer valuable insights for promoting safer spat collector alternatives such as BioM and contribute to the sustainable development of pearl farming.

Discovery and analysis of microplastics in human bone marrow

The health implications of human exposure to microplastics (MPs) have raised significant concerns. While evidence indicates MPs can accumulate in closed human organs like the heart, placenta, and blood, there is no available data on MP exposure specifically within the human bone marrow. To fill the research gap, this study detected the concentration of microplastics (MPs) in bone marrow samples by pyrolysis gas chromatography-mass spectrometry (Py-GC/MS) and assessed the size range and morphological characteristics of MPs by Laser Direct Infrared Spectroscopy (LD-IR) and scanning electron microscopy (SEM). Our study shows that MPs were present in all 16 bone marrow samples, with an average concentration of 51.29 µg/g ranging from 15.37 µg/g to 92.05 µg/g. Five polymer types-polyethylene (PE), polystyrene (PS), polyvinyl chloride (PVC), polyadiohexylenediamine 66 (PA66), and polypropylene (PP), were identified. PE was the most frequent polymer detected in the bone marrow, with an average concentration of 30.02 µg/g ranging from 14.77 µg/g to 52.57 µg/g, with a detection rate of 93.75 %. PS had the highest detection rate at 100 % of bone marrow samples, while PVC and PA66 were found in 75 % of samples each. LD-IR analysis revealed the identification of 25 polymer types, with an average abundance of 19.72 particles/g. Of these, 89.82 % of the MPs were smaller than 100 µm. In summary, this study has, for the first time, demonstrated the presence of MPs are deeply embedded within human bone marrow, providing a basis for future investigations into their potential toxicological effects and underlying mechanisms affecting the hematopoietic system.

Direct Mass Spectrometric Analysis of Brominated Flame Retardants in Synthetic Polymers

Brominated flame retardants (BFRs) are persistent organic pollutants that pose a major threat to the environment. In this study, a direct insertion probe (DIP) coupled with atmospheric pressure chemical ionization (APCI) quadrupole time-of-flight mass spectrometry (QTOF-MS) was used to characterize additives, especially BFRs, from solid polymer samples with minimal sample preparation. A temperature-programmed DIP analysis, from 150 to 450 °C within 10 min, was utilized to achieve temporal separation of analytes based on their boiling or degradation temperatures, thereby facilitating their easier identification within a single run. Studied BFRs showed different behaviors during the analysis: decabromodiphenyl ether and tetrabromobisphenol A were found to be stable within the studied temperature range, while hexabromocyclododecane already started to debrominate. Our study showed that the DIP-APCI-MS method suited well for the direct qualitative identification of BFRs from polymer matrices. Furthermore, by optimizing the sampling procedure with cryogenic grinding, even quantitative analysis could be performed. The DIP measurements also provided important information about the composition of polymer matrices, including the identification of the comonomers present. Overall, DIP-APCI QTOF-MS was found to be an excellent tool for the compositional analysis of plastic samples. Developing rapid and reliable analysis methods can pave the way for more efficient plastic recycling and the safer use of plastic recyclates.

Plastic breath: Quantification of microplastics and polymer additives in airborne particles

The widespread extensive use of synthetic polymers has led to a substantial environmental crisis caused by plastic pollution, with microplastics detected in various environments and posing risks to both human health and ecosystems. The possibility of plastic fragments to be dispersed in the air as particles and inhaled by humans may cause damage to the respiratory and other body systems. Therefore, there is a particular need to study microplastics as air pollutants. In this study, we tested a combination of analytical pyrolysis, gas chromatography-mass spectrometry, and gas and liquid chromatography-mass spectrometry to identify and quantify both microplastics and their additives in airborne particulate matter and settled dust within a workplace environment: a WEEE treatment plant. Using this combined approach, we were able to accurately quantify ten synthetic polymers and eight classes of polymer additives. The identified additives include phthalates, adipates, citrates, sebacates, trimellitates, benzoates, organophosphates, and newly developed brominated flame retardants.

A green approach for the automatic quantitative analysis of additives in plastic samples using in-tube extraction dynamic headspace sampling technique coupled to GC-MS/MS

BACKGROUND

Many of the chemicals frequently used as additives have been recognised as hazardous substances, and therefore their analysis is necessary to evaluate plastic contamination risk. Additives analysis in plastic samples is usually performed by methods involving high volumes of toxic solvents or having high detection limits. In this work, a novel, fast, solventless and reliable green method was developed for the automated analysis of plastic additives from plastic samples. The proposed method consists of in-tube extraction dynamic headspace sampling (ITEX-DHS) combined with gas chromatography (GC) and mass spectrometry (MS/MS) determination.

RESULTS

Several parameters affecting the ITEX-DHS extraction of 47 additives in plastic samples (including phthalates, bisphenols, adipates, citrates, benzophenones, organophosphorus compounds, among others) were optimised. The use of matrix-matched calibration, together with labelled surrogate standards, minimises matrix effects, resulting in recoveries between 70 and 128%, with good quantitation limits (below 0.1 μg g-1 for most compounds) and precision (<20%). The method proposed can be applied to any type of polymer, but due to the existence of the matrix effect, calibrates with the adequate matrix should be performed for each polymer.

SIGNIFICANCE

This method represents an effective improvement compared to previous methods because it is fast, solvent-free, fully automated, and provides reliable quantification of additives in plastic samples.

Identification and quantification of fluorinated polymers in consumer products by combustion ion chromatography and pyrolysis-gas chromatography-mass spectrometry

Total fluorine was determined in 45 consumer product samples from the Swedish market which were either suspected or known to contain fluorinated polymers. Product categories included cookware (70-550 000 ppm F), textiles (10-1600 ppm F), electronics (20-2100 ppm F), and personal care products (10-630 000 ppm F). To confirm that the fluorine was organic in nature, and deduce structure, a qualitative pyrolysis-gas chromatography-mass spectrometry (pyr-GC/MS) method was validated using a suite of reference materials. When applied to samples with unknown PFAS content, the method was successful at identifying polytetrafluoroethylene (PTFE) in cookware, dental products, and electronics at concentrations as low as 0.1-0.2 wt%. It was also possible to distinguish between 3 different side-chain fluorinated polymers in textiles. Several products appeared to contain high levels of inorganic fluorine. This is one of the few studies to quantify fluorine in a wide range of consumer plastics and provides important data on the concentration of fluorine in materials which may be intended for recycling, along with insights into the application of pyr-GC/MS for structural elucidation of fluorinated polymers in consumer products.

Improvement of the quantitativeness of the thermal desorption-GC/MS method and development of polystyrene certified reference material for the quantification of decabromodiphenyl ether (BDE 209) by using isotope dilution mass spectrometry

A polystyrene (PS) certified reference material (CRM) for the analysis of decabromodiphenyl ether (BDE 209) was issued. PS disk was prepared by injection molding of the mixture of versine PS and BDE 209. The certification of the PS CRM was conducted by two analytical methods with different sample preparation methods using isotope dilution mass spectrometry (IDMS). The certified value, wCRM, was 978 mg/kg, and this value coincided with the regulation value of BDE 209 in the Restriction of Hazardous Substances directive (1000 mg/kg). The uncertainties related to certification, uwmean, inhomogeneity, uhom, and long- and short-term instability, usts and ults, respectively, were evaluated based on the mass fraction of BDE 209. The uwmean, uhom, usts, and ults were 0.0265, 0.0046, 0.0061, and 0.0099 (relative), respectively, and the expanded uncertainty for this CRM was determined as 57 mg/kg (coverage factor is 2). Additionally, the quantitative capability of the thermal desorption-gas chromatography/mass spectrometry (TD-GC/MS) method was evaluated. In TD-GC/MS, the analytical values of the developed CRM obtained by the external and internal standard methods with matrix-free calibrants were out of the range of the wCRM (almost 10% larger or smaller), whereas those with matrix-matched calibrants agreed with the wCRM. In contrast to these results, the analytical values obtained by TD-GC/MS using IDMS were consistent with the wCRM no matter if matrix-free or matrix-matched calibrants were used. These results indicated that, for quantification of BDE 209 in PS, the trueness and precision of TD-GC/MS can be enhanced by applying IDMS without matrix-matched calibrants.

Towards the Understanding of the Aging Behavior of p-PVC in Close Contact with Minced Meat in the Artwork POEMETRIE by Dieter Roth

This paper presents scientific investigations into the materiality and aging behavior of a copy of Dieter Roth's multiple POEMETRIE (1968), mainly made of p-PVC components and minced meat, with the aim of informing conservation-restoration strategies. The main issues were represented by plasticizer migration, fat diffusion, and leakage, which led to the formation of a sticky surface layer. Replicas of p-PVC without minced meat were prepared and artificially thermally aged, while several techniques were used to investigate both the artwork and the replicas in terms of materials and degradation state. These include UV/Vis imaging, pH measurements, FTIR-ATR, and Py-GC/MS. In addition to showing that p-PVC-based materials composed of slightly different plasticizers were affected by similar degradation pathways (i.e., plasticizer migration, yellowing, etc.), this study reports that fat components were also shown to be unstable, resulting in migration/leakage in different directions, where their degradation amplified that of the p-PVC bags. This work represents a first study of plasticizer migration and fat diffusion in the art and conservation context. Also, an ammine-wax type of lubricant was identified in the most recent p-PVC formulations as the replicas selected for this study, thus providing an important source of information in different polymer-based research areas.

Recent Study of Separation and Identification of Micro- and Nanoplastics for Aquatic Products

Micro- and nanoplastics (MNPs) are polymeric compounds widely used in industry and daily life. Although contamination of aquatic products with MNPs exists, most current research on MNPs focuses on environmental, ecological, and toxicological studies, with less on food safety. Currently, the extent to which aquatic products are affected depends primarily on the physical and chemical properties of the consumed MNPs and the content of MNPs. This review presents new findings on the occurrence of MNPs in aquatic products in light of their properties, carrier effects, chemical effects, seasonality, spatiality, and differences in their location within organisms. The latest studies have been summarized for separation and identification of MNPs for aquatic products as well as their physical and chemical properties in aquatic products using fish, bivalves, and crustaceans as models from a food safety perspective. Also, the shortcomings of safety studies are reviewed, and guidance is provided for future research directions. Finally, gaps in current knowledge on MNPs are also emphasized.

Real-time morphological detection of label-free submicron-sized plastics using flow-channeled differential interference contrast microscopy

Owing to the surge in plastic waste generated during the COVID-19 pandemic, concerns regarding microplastic pollution in aqueous environments are increasing. Since microplastics (MPs) are broken down into submicron (< 1 µm) and nanoscale plastics, their real-time morphological detection in water is necessary. However, the decrease in the scattering cross-section of MPs in aqueous media precludes morphological detection by bright-field microscopy. To address this problem, we propose and demonstrate a differential interference contrast (DIC) system that incorporates a magnification-enhancing system to detect MPs in aqueous samples. To detect MPs in both the stationary and mobile phases, a microfluidic chip was designed, taking into consideration the imaging depth of focus and flow resistance. MPs of various sizes flowing in deionized, tap, and pond water at varying speeds were observed under Static and Flow conditions. Successful real-time morphological detection and quantification of polystyrene beads down to 200 nm at a constant flow rate in water were achieved. Thus, the proposed novel method can significantly reduce analysis time and improve the size-detection limit. The proposed DIC microscopy system can be coupled with Raman or infrared spectroscopy in future studies for chemical composition analysis. ENVIRONMENTAL IMPLICATION: Microplastics (MPs), particularly submicron plastics < 1-µm, can pose a risk to human health and aquatic ecosystems. Existing methods for detecting MPs in the aqueous phase have several limitations, including the use of expensive instruments and prolonged and labor-intensive procedures. Our results clearly demonstrated that a new low-cost flow-channeled differential interference contrast microscopy enables the real-time morphological detection and quantification of MPs down to 200 nm under flowing conditions without sample labeling. Consequently, our proposed rapid method for accurate quantitative measurements can serve as a valuable reference for detecting submicron plastics in water samples.

Effects of organic additives on spectroscopic and molecular-level features of photo-induced dissolved organic matter from microplastics

The environmental occurrence and impact of dissolved organic matter leached from microplastics (MP-DOM) has been the subject of increased research interest. Commercial plastics, which typically contain additives, are subject to natural weathering processes and can eventually lose their additives. However, the effects of organic additives in commercial microplastics (MPs) on the release of MP-DOM under UV irradiation remain poorly understood. In this study, four polymer MPs (polyethylene; PE, polypropylene; PP, polystyrene; PS, polyvinylchloride; PVC) and four commercial MPs, including a PE zip bag, a PP facial mask, a PVC sheet, Styrofoam, were subjected to leaching under UV irradiation, and the MP-DOM was characterized using Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS) and fluorescence excitation emission matrix-parallel factor analysis (EEM-PARAFAC). Although UV light promoted the leaching of MP-DOM from both MP groups, the amount released was more pronounced for the polymer MPs than for the commercial MPs. The commercial MP-DOM was characterized by a prominent protein/phenol-like component (C1), while a humic-like component (C2) prevailed in the polymer MPs. FT-ICR-MS identified a higher number of unique molecular formulas for the commercial than for the polymer MP-DOM. The unique molecular formulas of commercial MP-DOM included known organic additives and other breakdown products, while the polymer MP-DOM featured more pronounced unsaturated carbon structures in its identified unique formulas. Several molecular-level parameters showed significant correlations with fluorescence properties, such as CHO formulas (%) with C1 and condensed aromatic structure (CAS-like, %) with C2, suggesting the potential application of fluorescent components as an optical descriptor for the complex molecular-level composition. This study also revealed the possible high environmental reactivity of both polymer MPs and fully weathered plastics due to the unsaturated structures generated in sunlit environments.

A Thermal Analytical Study of LEGO® Bricks for Investigating Light-Stability of ABS

Acrylonitrile butadiene styrene (ABS) is a thermoplastic polymer widely used in several everyday life applications; moreover, it is also one of the most employed plastics in contemporary artworks and design objects. In this study, the chemical and thermal properties of an ABS-based polymer and its photo-degradation process were investigated through a multi-analytical approach based on thermal, mass spectrometric and spectroscopic techniques. LEGO® building blocks were selected for studying the ABS properties. First, the composition of unaged LEGO® bricks was determined in terms of polymer composition and thermal stability; then, the bricks were subjected to UV-Vis photo-oxidative-accelerated ageing for evaluation of possible degradation processes. The modifications of the chemical and thermal properties were monitored in time by a multi-technique approach aimed at improving the current knowledge of ABS photodegradation, employing pyrolysis online with gas chromatography and evolved gas analysis, coupled with mass spectrometric detection (Py-GC-MS and EGA-MS), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and corroborated by external reflection FT-IR spectroscopy. The multimodal approach provided new evidence on the two-step degradation pathway proposed for ABS, defining molecular markers for polybutadiene oxidation and styrene-acrylonitrile depolymerization. Moreover, the results highlighted the feasibility of correlating accurate compositional and thermal data acquired by bulk techniques with external reflection FT-IR spectroscopy as a non-invasive portable tool to monitor the state of conservation of plastic museum objects in-situ.

A novel measurement strategy and a dedicated sampling cell for the parallel characterization of organic and inorganic constituents in polymer samples by concurrent laser ablation ICP-OES and EI-MS

Polymeric composite materials are gaining importance due to their universal applicability and easy adaptability for their intended use. For the comprehensive characterization of these materials, the concurrent determination of the organic and the elemental constituents is necessary, which cannot be provided by classical analysis methods. In this work, we present a novel approach for advanced polymer analysis. The proposed approach is based on firing a focused laser beam onto a solid sample placed in an ablation cell. The generated gaseous and particular ablation products are measured online parallelly by EI-MS and ICP-OES. This bimodal approach allows direct characterization of the main organic and inorganic constituents of solid polymer samples. The LA-EI-MS data showed excellent agreement with the literature EI-MS data allowing not only the identification of pure polymers but also of copolymers, as demonstrated with acrylonitrile butadiene styrene (ABS) as the sample. The concurrent collection of ICP-OES elemental data is vital for classification, provenance determination, or authentication studies. The applicability of the proposed procedure has been demonstrated by analysis of various polymer samples from everyday use.

Organic chemicals associated with rubber are more toxic to marine algae and bacteria than those of thermoplastics

The current study investigated the chemical complexity of fifty plastic (36) and elastomer/rubber (14) methanol extracts from consumer products, focusing on the association with toxicity in two screening assays (bacteria luminescence and marine microalgae). The chemical composition varied considerably between the products and polymers. The most complex sample (car tire rubber) contained 2456 chemical features and the least complex (disposable water bottle) only 39 features, with a median of 386 features across all products. Individual extract toxicity also varied significantly across the products and polymers, with the two toxicity assays showing comparable results in terms of defining low and high toxicity extracts, and correlation between medium toxicity extracts. Chemical complexity and abundance both correlated with toxicity in both assays. However, there were strong differences in toxicity between plastic and elastomer extracts. Overall, 86-93 % of the 14 elastomer extracts and only 33-36 % of other polymer extracts (n = 36) were more toxic than the median. A range of compounds were tentatively identified across the sample set, with several concerning compounds being identified, mostly in the elastomers. While the current focus on plastic chemicals is towards thermoplastics, we show that elastomers may be of more concern from an environmental and human health perspective.

Comprehensive analysis of common polymers using hyphenated TGA-FTIR-GC/MS and Raman spectroscopy towards a database for micro- and nanoplastics identification, characterization, and quantitation

Environmental contamination by micro- and nanoplastics (MNPs) is well documented with potential for their increased accumulation globally. Growing public concern over environmental, ecological, and human exposure to MNPs has led to exponential increase in publications, news articles, and reports (Casillas et al., 2023). Significant knowledge gap exists in standardized analytical methods for the identification and quantification of MNPs from real world environmental samples. Here, we report comprehensive datasets utilizing thermogravimetric analyzer (TGA) coupled to a Fourier transformed infrared spectrometer (FTIR) and a gas chromatography/mass spectrometer (GC/MS) with corresponding Raman spectral data for the most common polymers documented to be present in the environment (35 plastics of 12 polymer types), to serve as a base line reference for the identification and quantitation of MNPs. Various parameters for TGA-FTIR-GC/MS data acquisition were optimized. Commercial consumer plastic product compositions were identified using this analytical database. Case studies to showcase the utility of the method for polymer mixtures analysis is included. This dataset would serve towards the development of a collaborative, global, comprehensive, and curated public database for the identification of various MNPs and mixtures.

Carbon nanotubes production from real-world waste plastics and the pyrolysis behaviour

The investigation of the pyrolysis behaviour of real-world waste plastics (RWWP) and using them as the feedstock to produce carbon nanotubes (CNTs) could serve as an effective solution to address the global waste plastics catastrophe. This research aimed to characterize the pyrolysis behaviour of RWWP via thermogravimetric analysis (TG) and fast pyrolysis-TG/mass spectrometry (Py-TG/MS) analyses. Activation energies (131.04 kJ mol^-1 -171.04 kJ mol^-1) for RWWP pyrolysis were calculated by three methods: Flynn-Wall-Ozawa (FWO) method, Kissinger-Akahira-Sunose (KAS) method, and Starink method. Py-TG/MS results indicated that the RWWP could be identified as polystyrene (RWWP-1), polyethylene (RWWP-2), polyethylene terephthalate (RWWP-3, 4), and polypropylene (RWWP-5, 6). In addition, RWWP-1, 2, 5, 6 outperform RWWP-3 and 4 as sources of carbon for producing CNTs. The results showed a high carbon yield of 32.21 wt% and a high degree of CNT purity at 93.04%.

The contribution of high-resolution GC separations in plastic recycling research

One convenient strategy to reduce environmental impact and pollution involves the reuse and revalorization of waste produced by modern society. Nowadays, global plastic production has reached 367 million tons per year and because of their durable nature, their recycling is fundamental for the achievement of the circular economy objective. In closing the loop of plastics, advanced recycling, i.e., the breakdown of plastics into their building blocks and their transformation into valuable secondary raw materials, is a promising management option for post-consumer plastic waste. The most valuable product from advanced recycling is a fluid hydrocarbon stream (or pyrolysis oil) which represents the feedstock for further refinement and processing into new plastics. In this context, gas chromatography is currently playing an important role since it is being used to study the pyrolysis oils, as well as any organic contaminants, and it can be considered a high-resolution separation technique, able to provide the molecular composition of such complex samples. This information significantly helps to tailor the pyrolysis process to produce high-quality feedstocks. In addition, the detection of contaminants (i.e., heteroatom-containing compounds) is crucial to avoid catalytic deterioration and to implement and design further purification processes. The current review highlights the importance of molecular characterization of waste stream products, and particularly the pyrolysis oils obtained from waste plastics. An overview of relevant applications published recently will be provided, and the potential of comprehensive two-dimensional gas chromatography, which represents the natural evolution of gas chromatography into a higher-resolution technique, will be underlined.

A review on pollutants remediation competence of nanocomposites on contaminated water

Clean freshwater has been required for drinking, sanitation, agricultural activities, and industry, as well as for the development and maintenance of the eco - systems on which all livelihoods rely. Water contamination is currently a significant concern for researchers all over the world; hence it is essential that somehow this issue is resolved as soon as possible. It is now recognised as one of the most important research areas in the world. Current wastewater treatment techniques degrade a wide range of wastewaters efficiently; however, such methods have some limitations. Recently, nanotechnology has emerged as a wonderful solution, and researchers are conducting research in this water remediation field with a variety of potential applications. The pollutants remediation capability of nanocomposites as adsorbents, photocatalysts, magnetic separation, and so on for contaminant removal from contaminated water has been examined in this study. This study has spotlighted the most significant nanocomposites invention reported to date for contaminated and effluent remediation, as well as a research gap as well as possible future perspectives.

Detection methods of micro and nanoplastics

Plastics and related contaminants (including microplastics; MPs and nanoplastics; NPs) have become a serious global safety issue due to their overuse in many products and applications and their inadequate management, leading to possible leakage into the environment and eventually to the food chain and humans. There is a growing literature reporting on the occurrence of plastics, (MPs and NPs) in both marine and terrestrial organisms, with many indications about the harmful impact of these contaminants on plants and animals, as well as potential human health risks. The presence of MPs and NPs in many foods and beverages including seafood (especially finfish, crustaceans, bivalves, and cephalopods), fruits, vegetables, milk, wine and beer, meat, and table salts, has become popular research areas in recent years. Detection, identification, and quantification of MPs and NPs have been widely investigated using a wide range of traditional methods, such as visual and optical methods, scanning electron microscopy, and gas chromatography-mass spectrometry, but these methods are burdened with a number of limitations. In contrast, spectroscopic techniques, especially Fourier-transform infrared spectroscopy and Raman spectroscopy, and other emerging techniques, such as hyperspectral imaging are increasingly being applied due to their potential to enable rapid, non-destructive, and high-throughput analysis. Despite huge research efforts, there is still an overarching need to develop reliable analytical techniques with low cost and high efficiency. Mitigation of plastic pollution requires establishing standard and harmonized methods, adopting holistic approaches, and raising awareness and engaging the public and policymakers. Therefore, this chapter focuses mainly on identification and quantification techniques of MPs and NPs in different food matrices (mostly seafood).

A Review on Catalytic Fast Co-Pyrolysis Using Analytical Py-GC/MS

Py-GC/MS combines pyrolysis with analytical tools of gas chromatography (GC) and mass spectrometry (MS) and is a quick and highly effective method to analyse the volatiles generated from small amounts of feeds. The review focuses on using zeolites and other catalysts in the fast co-pyrolysis of various feedstocks, including biomass wastes (plants and animals) and municipal waste materials, to improve the yield of specific volatile products. The utilisation of zeolite catalysts, including HZSM-5 and nMFI, results in a synergistic reduction of oxygen and an increase in the hydrocarbon content of pyrolysis products. The literature works also indicate HZSM-5 produced the most bio-oil and had the least coke deposition among the zeolites tested. Other catalysts, such as metals and metal oxides, and feedstocks that act as catalysts (self-catalysis), such as red mud and oil shale, are also discussed in the review. Combining catalysts, such as metal oxides and HZSM-5, further improves the yields of aromatics during co-pyrolysis. The review highlights the need for further research on the kinetics of the processes, optimisation of feed-to-catalyst ratios, and stability of catalysts and products.

Dielectric barrier discharge plasma for the remediation of microplastic-contaminated soil from landfill

The huge amount of plastic waste accumulated in landfills has caused serious microplastic (MP) pollution to the soil environment, which has become an urgent issue in recent years. It is challenging to deal with the non-biodegradable MP pollutants in actual soil from landfills. In this study, a coaxial dielectric barrier discharge (DBD) system was proposed to remediate actual MP-contaminated landfill soil due to its strong oxidation capacity. The influence of carrier gas type, applied voltage, and air flow rate was investigated, and the possible degradation pathways of MP pollutants were suggested. Results showed the landfill soil samples contained four common MP pollutants, including polyethylene (PE), polypropylene (PP), polystyrene (PS), and polyvinyl chloride (PVC) with sizes ranging from 50 to 1500 μm. The MP pollutants in the soil were rapidly removed under the action of reactive oxygen species (ROS) generated by DBD plasma. Under the air flow rate of 1500 mL min^-1, the maximum remediation efficiency represented by mass loss reached 96.5% after 30 min treatment. Compared with nitrogen, when air was used as the carrier gas, the remediation efficiency increased from 41.4% to 81.6%. The increased applied voltage from 17.5 to 24.1 kV could also promote the removal of MP contaminants. Sufficient air supply was conducive to thorough removal. However, when the air flow rate reached 1500 mL min^-1 and continued to rise, the final remediation efficiency would be reduced due to the shortened residence time of ROS. The DBD plasma treatment proposed in this study showed high energy efficiency (19.03 mg kJ^-1) and remediation performance (96.5%). The results are instructive for solving MP pollution in the soil environment.

Advances and prospects of carbon dots for microplastic analysis

Microplastics have become the world's most emerging pollutants today due to the ubiquitous use of plastics in everyday life and their ability to migrate from micro to nanoscale to every corner of the natural world, leading to ecological imbalances and global catastrophes. However, a standardized method for separating and analyzing microplastics from actual food or environmental samples has not been established. Therefore, it is necessary to develop a simple, fast, cost-effective, and accurate method that can accurately measure the degree of contamination of microplastics. As one of these methods, fluorometry has been proposed as a cost-effective method to detect, quantify and differentiate individual plastic particles. Therefore, this review discussed the technique for analyzing microplastics using fluorescent carbon dots (CDs). This review provided an overview of the impact of microplastics and the feasibility of using CDs to detect and analyze microplastics. In particular, this review will discuss novel microplastic analysis methods using CD and future application studies. The method using CDs will overcome the limitations of current microplastic analysis technology and may become a new method for detecting and analyzing microplastics.

Qualitative characterisation and identification of microplastics in a freshwater dam at Gauteng Province, South Africa, using pyrolysis-gas chromatography-time of flight-mass spectrometry (Py-GC-ToF-MS)

Pyrolysis GC-ToF-MS-based analytical study was employed in the identification of microplastics (MPs) in the freshwater of a dam Rietvlei (RTV) located at Gauteng Province, South Africa. These MPs extracted in five locations of the dam were found to contain five different plastic polymeric constituents including PE, PS, PA, PVC and PET along with phthalate esters and fatty acid (amides and esters) derivatives as additives. Based on the fragmented pyrolyzate products, the contribution of plastic polymers and additives was 74% and 26% respectively. Among polymers, PA was dominant with 52% followed by PVC (16%) and others (13%) such as PE, PET and PS in MPs. Scanning electron micrographs of MPs in this aquatic body displayed the rough and fibrous typed patterns. The residual mass of 8-14% was left after the thermal degradation of MPs in RTV samples in the temperature range of 500-550 °C. The results of thermogravimetry (TGA) and energy-dispersive (EDS) analyses are mutually dependent and coherent to each other by way of demonstrating the presence of various inorganic compounds in the form of additives and/or sorbates. The lessened intensities of carbonyl stretching in PA (1625 cm-1) and PET (1725 cm-1) type of MPs attributed the occurrence of degradation and weathering in this aquatic system. The possible causes to the contamination of MPs in this freshwater are the located industries and poor waste management strategies being practised in this densely populated city. Based on the industry, waste management and population perspectives, the increased contamination of MPs is very likely in this freshwater which will drastically affect the ecosystem in the near future. Based on the characterisation results, the presence of various polymers, additives and the metals in MPs is envisaged to deteriorate the aquatic life along with successive risks for the people as a consequence of bio-magnification.

The characterization and influence factors of semi-volatile compounds from mechanically recycled polyethylene terephthalate (rPET) by combining GC×GC-TOFMS and chemometrics

A non-targeted method was developed for screening the semi-volatile compounds of different mechanically recycled PET intended for food contact materials. The data was further analyzed by multiple chemometrics methods to obtain the difference level, and the potential influence factors were investigated. The results showed that total dissolution with comprehensive two-dimensional gas chromatography coupled with time-of-flight mass spectrometry was more effective than other reported methods. Based on the difference level, 97 compounds were characterized into 4 levels. 1-Methyl-2-pyrrolidinone originating from organic solvent was recognized as level IV and could be determined as the primary difference indicator. The contaminant is mainly attributed to the residuum derived from non-food consumer products. The specific types of contaminants and process parameters of the recycling, such as moisture content, properties of rPET, and temperature, were the potential key factors affecting the presence of semi-volatile compounds of mechanically recycled rPET.

Utilizing Pyrolysis-Gas Chromatography/Mass Spectrometry for Monitoring and Analytical Characterization of Microplastics in Polychaete Worms

Microplastics (the term for plastics at sizes of <5 mm) might be introduced into the environment from domestic or agricultural activities or from the breakdown of plastic pieces, particles, and debris that are bigger in size. Their presence in the aquatic environment has caused accumulation problems, as microplastics do not easily break down and can be digested by some aquatic organisms. This study was conducted to screen and monitor the level of microplastic pollution in polychaete worms using pyrolysis−gas chromatography/mass spectrometry (Py-GC/MS). The study was conducted in Setiu Wetlands, Malaysia from November 2015 to January 2017 at five-month intervals and covered all monsoon changes. Results from physical and visual analyses indicated that a total number of 371.4 ± 20.2 items/g microplastics were retrieved from polychaete for all seasons, in which, the majority comprised transparent microplastics (49.87%), followed by brown with 138.3 ± 13.6 items/g (37.24%), 21.7 ± 1.9 items/g for blue (5.84%), and 12.9 ± 1.1 items/g for black (3.47%), while the remaining were green and grey-red colors. Statistical analysis using Kruskal−Wallis showed insignificant differences (p > 0.05) between the sampling station and period for the presence of a microplastics amount. Most of the microplastics were found in fiber form (81.5%), whereas the remaining comprised fragment (18.31%) and film (0.19%) forms. Further analysis with Py-GC/MS under a selective ion monitoring mode indicated that pyrolytic products and fragment ions for a variety of polymers, such as polyvinyl chloride, polypropylene, polyethylene, polyethylene terephthalate, polyamide, and polymethylmethacrylate, were detected. This study provides an insightful application of Py-GC/MS techniques for microplastics monitoring, especially when dealing with analytical amounts of samples.

Research on the pyrolysis characteristics and mechanisms of waste printed circuit boards at fast and slow heating rates

The pyrolysis treatment of waste printed circuit boards (WPCBs) shows great potential for sustainable treatment and hazard reduction. In this work, based on thermogravimetry (TG), pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS), and density functional theory (DFT), the thermal weight loss, product distribution, and kinetics of WPCBs pyrolysis were studied by single-step and multi-step pyrolysis at fast (600 °C/min) and slow (10 °C/min) heating rates. The heating rates of TG and Py-GC/MS were the same for each group of experiments. In addition, the bond dissociation energy (BDE) of WPCBs polymer monomers was calculated by DFT method. Compared with slow pyrolysis, the final weight loss of fast pyrolysis is reduced by 0.76 wt%. The kinetic analysis indicates that the activation energies of main pyrolysis stages range from 98.29 kJ/mol to 177.59 kJ/mol. The volatile products of fast pyrolysis are mainly phenols and aromatics. With the increase of multi-step pyrolysis temperature, the order of the escaping volatiles is phenols, hydrocarbyl phenols, aromatics, and benzene (or diphenyl phenol). The pyrolysis residue of WPCBs may contains phenolics and polymers. Based on the free radical reactions, the mechanism and reaction pathways of WPCBs pyrolysis were deduced by the DFT. Moreover, a large amount of benzene is produced by pyrolysis, and its formation mechanism was elaborated.

A review of analytical methods and models used in atmospheric microplastic research

Microplastic pollution in the environment has become a source of concern in recent years. The transport and deposition of suspended atmospheric microplastics play an important role in the global linkage of microplastic sources and sinks. In this review, we summarized recent research progress on sampling devices, pretreatments, and identification methods for atmospheric microplastics. The total suspended particles and atmospheric deposition, including dust, rainfall, and snow samples, are the environmental carriers for atmospheric microplastic studies. There are active and passive sampling methods. Pretreatment depends on sample types and identification methods and includes sieving, digestion, density separation, filtration, and drying. The measured features for atmospheric microplastics include particle size distributions, shapes, colors, surface morphology, and polymer compositions, using stereomicroscopes, Fourier transform infrared spectroscopy, scanning electron microscopy, Raman spectroscopy, and liquid chromatography-tandem mass spectrometry. Laser direct infrared spectroscopy and thermochemical methods coupled with mass spectrometry are potential methods for identifying atmospheric microplastics. Currently, models for estimating the fluxes of atmospheric microplastic emission, transport, and deposition are in the initial stages of development; their implementation will enhance our understanding of the "microplastic cycle" globally based on simulated and observed data.

Analysis of Plastic-Derived Fuel Oil Produced from High- and Low-Density Polyethylene

The exponential growth of waste plastic accumulation has had an irreversible and lasting impact on the world. An imminent threat to marine and terrestrial ecosystems of massive proportions, plastic waste accumulation is a global problem that will not only have to be tackled by current generations but for many generations to follow. The scale of current recycling technologies and efforts to reduce consumption by for-profit and non-profit institutions, governments, and consumers will need to be rapidly increased to combat the negative impacts plastic waste has had on the planet since its conception. This is especially the case in areas with limited infrastructure to properly collect, manage, and dispose of plastic waste. Solutions to plastic waste accumulation crisis that are appropriate for the developing world are urgently needed. Conversion of plastic waste to liquid fuel by slow pyrolysis is a technology that is particularly suitable for developing countries due to its ability to convert polyolefin waste plastic into a useful product, thus preventing its eventual accumulation in the ecosystem. However, in developing countries, conversion techniques that do not rely on sophisticated technologies are needed. Since processing time and operating temperature are the simplest variables to control, an analytical study has been conducted to assess how the molecular composition of plastic derived fuel oil (PDFO) is impacted by these parameters. The results of gas chromatography-mass spectrometry (GC-MS) and thermogravimetric analysis (TGA) studies of PDFO from high- and low-density polyethylene plastic waste produced using appropriate technology techniques are presented alongside a comparison with traditional diesel fuel and kerosene. This approach is novel in that it differs from previously conducted research, which has studied the use of catalysts, additives, or single operating temperatures to assess the composition of PDFO. Therefore, this research contribution presents a simplistic and inexpensive approach for tuning PDFO composition in appropriate technology settings.

The micro-, submicron-, and nanoplastic hunt: A review of detection methods for plastic particles

Plastic particle pollution has been shown to be almost completely ubiquitous within our surrounding environment. This ubiquity in combination with a variety of unique properties (e.g. density, hydrophobicity, surface functionalization, particle shape and size, transition temperatures, and mechanical properties) and the ever-increasing levels of plastic production and use has begun to garner heightened levels of interest within the scientific community. However, as a result of these properties, plastic particles are often reported to be challenging to study in complex (i.e. real) environments. Therefore, this review aims to summarize research generated on multiple facets of the micro- and nanoplastics field; ranging from size and shape definitions to detection and characterization techniques to generating reference particles; in order to provide a more complete understanding of the current strategies for the analysis of plastic particles. This information is then used to provide generalized recommendations for researchers to consider as they attempt to study plastics in analytically complex environments; including method validation using reference particles obtained via the presented creation methods, encouraging efforts towards method standardization through the reporting of all technical details utilized in a study, and providing analytical pathway recommendations depending upon the exact knowledge desired and samples being studied.

The impact of nano/micro-plastics toxicity on seafood quality and human health: facts and gaps

Contamination of the food and especially marine environment with nano/micro-plastic particles has raised serious concern in recent years. Environmental pollution and the resulting seafood contamination with microplastic (MP) pose a potential threat to consumers. The absorption rate of the MP by fish is generally considered low, although the bioavailability depends on the physical and chemical properties of the consumed MP. The available safety studies are inconclusive, although there is an indication that prolonged exposure to high levels of orally administered MP can be hazardous for consumers. This review details novel findings about the occurrence of MP, along with its physical and chemical properties, in the marine environment and seafood. The effect of processing on the content of MP in the final product is also reviewed. Additionally, recent findings regarding the impact of exposure of MP on human health are discussed. Finally, gaps in current knowledge are underlined, and the possibilities for future research are indicated in the review. There is an urgent need for further research on the absorption and bioavailability of consumed MP and in vivo studies on chronic exposure. Policymakers should also consider the implementation of novel legislation related to MP presence in food.

Three-Dimensional Mass Spectral Imaging of Polymers Via Laser-Assisted Micro-Pyrolysis Program with Flowing Atmospheric-Pressure Afterglow Ambient Mass Spectrometry

Herein, a novel diode laser-assisted micro-pyrolysis program (LAMP) technique is demonstrated and coupled with flowing atmospheric-pressure afterglow ambient mass spectrometry for instantaneously profiling polymers and polymer additives. Laser power modulation allows thermal separation of additives and different pyrolysis products, as shown through positive- and negative-mode high-resolution mass spectra and Kendrick mass defect plots of homopolymers, copolymers, polymer blends, and complex polymer samples. LAMP allows much faster temperature control through real-time duty cycle changes and gives significantly better spatial confinement compared to typical resistive heating pyrolysis approaches. Finally, MS imaging, with lateral and depth resolution, is demonstrated for a complex polymer pressure-sensitive adhesive tape sample.

Photoluminescence-Based Techniques for the Detection of Micro- and Nanoplastics

The growing numbers related to plastic pollution are impressive, with ca. 70 % of produced plastic (>350 tonnes/year) being indiscriminately wasted in the environment. The most dangerous forms of plastic pollution for biota and human health are micro- and nano-plastics (MNPs), which are ubiquitous and more bioavailable. Their elimination is extremely difficult, but the first challenge is their detection since existing protocols are unsatisfactory for microplastics and mostly absent for nanoplastics. After a discussion of the state of the art for MNPs detection, we specifically revise the techniques based on photoluminescence that represent very promising solutions for this problem. In this context, Nile Red staining is the most used strategy and we show here its pros and limitations, but we also discuss other more recent approaches, such as the use of fluorogenic probes based on perylene-bisimide and on fluorogenic hyaluronan nanogels, with the added values of biocompatibility and water solubility.

Microplastics in the environment: Sampling, pretreatment, analysis and occurrence based on current and newly-exploited chromatographic approaches

The omnipresent character of microplastics (MPs) in environmental matrices, organisms and products has recently posed the need of their qualitative as well as quantitative analysis imperative, in order to provide data about their abundance and specification of polymer types in several substrates. In this framework, current and emerging approaches based on the chromatographic separation are of increased relevance in the field of MPs analysis and possess a large number of merits, since most of them are applicable in various complex matrices, sensitive and ideal for the detection of small-sized particles, whereas the common absence of any special pre-treatment step before analysis should also be highlighted. Αnalytical pyrolysis coupled with gas chromatography mass spectrometry (GC-MS) has recently gained ground as a powerful means to deliver information on MPs composition and degradation after their release into environment. Several instrumentations and trends in the area of analytical pyrolysis are thoroughly described within this review, while newly-exploited chromatographic methods in the field of MPs analysis, including Liquid Chromatography (LC) and Gel Permeation Chromatography (GPC) in this line are also investigated. The present review fills the gap of standardization concerning sampling, pre-treatment and chromatographic approaches and gathers all the available methodologies applied inside this area in accordance with the studied substrate, with the most examined environmental matrices being the solid one. After investigating the various works, some development options arise and it appears that chromatographic approaches should focus on improved extraction processes in terms of MPs isolation, since it is a crucial part in plastic items monitoring and is commonly depended on the polymer type and matrix. Special attention is given on the potential of chromatographic techniques for microplastics identification as well as quantification by confirming the current research status and knowledge gaps and highlighting some of the recent trends in this field.

BTEX recovery from waste rubbers by catalytic pyrolysis over Zn loaded tire derived char

Recovering valuable chemicals (BTEX: Benzene, toluene, ethylbenzene, and xylene) via catalytic pyrolysis of waste tires is a promising and sustainable approach. Zinc loaded tire derived char (TDC) was used as cheap catalyst for recovering valuable BTEX products from waste tire through pyrolysis in this study. The catalytic capability of TDC on BTEX production were experimentally investigated with respect to Zn content, catalytic temperature, and catalyst-to-tire ratio. Due to the abundant acid sites on the surface, the TDC showed notable catalytic capability for improving BTEX yield which was 2.4 times higher than that from uncatalyzed case. The loading of additional Zn increased the acid sites on the TDC and the catalytic performance was further improved. The increase of catalytic temperature and catalyst-to-tire ratio favored the formation of BTEX, but it also brought undesirable consequences, such as the mass loss of tire pyrolysis oil (TPO) and the formation of polycyclic aromatic hydrocarbons. The optimal TPO products were obtained at 600 °C with catalyst-to-tire ratio of 20. At this condition, the relative content of BTEX reached 54.70% and the cumulative BTEX yield was 10.13 wt%, increasing by 5.95 times compared to that of non-catalytic condition. This work provided a novel strategy of replacing traditional expensive catalysts with low-cost and effective carbon-based materials in the field of catalytic pyrolysis of waste tires.