Assessment of a new method for the analysis of decomposition gases of polymers by a combining thermogravimetric solid-phase extraction and thermal desorption gas chromatography mass spectrometry

Plastic Quantification and Polyethylene Overestimation in Agricultural Soil Using Large-Volume Pyrolysis and TD-GC-MS/MS

Quantification of microplastics in soil is needed to understand their impact and fate in agricultural areas. Often, low sample volume and removal of organic matter (OM) limit representative quantification. We present a method which allows simultaneous quantification of microplastics in homogenized, large environmental samples (>1 g) and tested polyethylene (PE), polyethylene terephthalate (PET), and polystyrene (PS) (200-400 μm) overestimation by fresh and diagenetically altered OM in agricultural soils using a new combination of large-volume pyrolysis adsorption with thermal desorption-gas chromatography-tandem mass spectrometry (TD-GC-MS/MS). Characteristic MS/MS profiles for PE, PET, and PS were derived from plastic pyrolysis and allowed for a new mass separation of PET. Volume-defined standard particles (125 × 125 × 20 μm3) were developed with the respective weight (PE: 0.48 ± 0.12, PET: 0.50 ± 0.10, PS: 0.31 ± 0.08 μg), which can be spiked into solid samples. Diagenetically altered OM contained compounds that could be incorrectly identified as PE and suggest a mathematical correction to account for OM contribution. With a standard addition method, we quantified PS, PET, and PEcorrected in two agricultural soils. This provides a base to simultaneously quantify a variety of microplastics in many environmental matrices and agricultural soil.

Parts-Per-Million Carbonate Mineral Quantification with Thermogravimetric Analysis-Mass Spectrometry

Mitigating the deleterious effects of climate change requires the development and implementation of carbon capture and storage technologies. To expand the monitoring, verification, and reporting (MRV) capabilities of geologic carbon mineralization projects, we developed a thermogravimetric analysis-mass spectrometry (TGA-MS) methodology to enable quantification of <100 ppm calcite (CaCO3) in complex samples. We extended TGA-MS calcite calibration curves to enable a higher measurement resolution and lower limits of quantification for evolved CO2 from a calcite-corundum mixture. We demonstrated <100 ppm carbonate mineral quantification with TGA-MS for the first time, an outcome applicable across earth, environmental, and materials science fields. We applied this carbonate quantification method to a suite of Columbia River Basalt Group (CRBG) well cuttings recovered in 2009 from Pacific Northwest National Laboratory's Wallula #1 Well. Our execution of this new combined calcite and calcite-corundum calibration curve TGA-MS method on our CRBG sample suite indicated average carbonate contents of 0.050 wt % in flow interiors (caprocks) and 0.400 wt % in interflow zones (reservoirs) in the upper 1250 m of the Wallula #1 Well. By advancing our knowledge of continental flood basalt-hosted carbonates in the mafic subsurface and reaching new TGA-MS quantification limits for carbonate minerals, we expand MRV capabilities and support the commercial-scale deployment of carbon mineralization projects in the Pacific Northwest United States and beyond.

Microplastics as vectors of other contaminants: Analytical determination techniques and remediation methods

The ubiquitous and persistent presence of microplastics (MPs) in aquatic and terrestrial ecosystems has raised global concerns due to their detrimental effects on human health and the natural environment. These minuscule plastic fragments not only threaten biodiversity but also serve as vectors for contaminants, absorbing organic and inorganic pollutants, thereby causing a range of health and environmental issues. This review provides an overview of microplastics and their effects. This work highlights available analytical techniques for detecting and characterizing microplastics in different environmental matrices, assessing their advantages and limitations. Additionally, this review explores innovative remediation approaches, such as microbial degradation and other advanced methods, offering promising prospects for combatting microplastic accumulation in contaminated environments. The focus on environmentally-friendly technologies, such as the use of microorganisms and enzymes for microplastic degradation, underscores the importance of sustainable solutions in plastic pollution management. In conclusion, this article not only deepens our understanding of the microplastic issue and its impact but also advocates for the urgent need to develop and implement effective strategies to mitigate this critical environmental challenge. In this context, the crucial role of advanced technologies, like quantitative Nuclear Magnetic Resonance spectroscopy (qNMR), as promising tools for rapid and efficient microplastic detection, is emphasized. Furthermore, the potential of the enzyme PETase (polyethylene terephthalate esterase) in microplastic degradation is examined, aiming to address the growing plastic pollution, particularly in saline environments like oceanic ecosystems. These innovations offer hope for effectively addressing microplastic accumulation in contaminated environments and minimizing its adverse impacts.

Micro(nano)plastics in commercial foods: A review of their characterization and potential hazards to human health

Micro (nano)plastics (MNPs) are pollutants of worldwide concern for their ubiquitous environmental presence and associated impacts. The higher consumption of MNPs contaminated commercial food can cause potential adverse human health effects. This review highlights the evidence of MNPs in commercial food items and summarizes different sampling, extraction, and digestion techniques for the isolation of MNPs, such as oxidizing digestion, enzymatic digestion, alkaline digestion and acidic digestion. Various methods for the characterization and quantification of microplastics (MPs) are also compared, including μ-Raman spectroscopy, μ-Fourier transform infrared spectroscopy (FTIR), thermal analysis and Scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDX). Finally, we share our concerns about the risks of MNPs to human health through the consumption of commercial seafood. The knowledge of the potential human health impacts at a subcellular or molecular level of consuming mariculture products contaminated with MNPs is still limited. Moreover, MNPs are somewhat limited, hard to measure, and still contentious. Due to the nutritional significance of fish consumption, the risk of exposure to MNPs and the associated health effects are of the utmost importance.

A critical review on nanoplastics and its future perspectives in the marine environment

Nanoplastics (plastic particles smaller than 1 μm) are the least-known type of marine litter. Nanoplastics (NPs) have attracted much interest in recent years because of their prevalence in the environment and the potential harm they can cause to living organisms. This article focuses on understanding NPs and their fate in the marine environment. Sources of NPs have been identified, including accidental release from products or through nano-fragmentation of larger plastic debris. As NPs have a high surface area, they may retain harmful compounds. The presence of harmful additives in NPs poses unique practical challenges for studies on their toxicity. In this review, several methods specifically adapted for the physical and chemical characterization of NPs have been discussed. Furthermore, the review provides an overview of the translocation and absorption of NPs into organisms, along with an evaluation of the release of potential toxins from NPs. Further, we have provided an overview about the existing methods suggested for the possible degradation of these NPs. We conclude that the hazards of NPs are plausible but unknown, necessitating a thorough examination of NPs' sources, fate, and effects to better mitigate and spread awareness about this emerging contaminant.

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.

Sampling strategies and analytical techniques for assessment of airborne micro and nano plastics

The atmosphere is pervasively polluted by microplastics and nano plastics (M/NPs) released into indoor and outdoor areas. However, various methodologies and their limitations along with non-standardization make the comparison of information concerning their prevalence difficult. Such diversity in techniques greatly limits the interpretation of results. Herein, We extracted data from publications on PubMed and Embase database up to the year 2022 regarding sampling strategies, identification methods, and reporting data for M/NPs quantification. In this review, 5 major areas for measuring airborne M/NPs have been identified including pre-sampling/ sampling/ post-sampling/ analysis/ and contamination avoidance. There are many challenges specific to each of those sections that need to be resolved through further method development and harmonization. This review mainly focuses on the different methods for collecting atmospheric M/NPs and also the analytical tools which have been used for their identification. While passive sampling is the most user-friendly method, the most precise and reproducible approach for collecting plastic particles is an active method which is directly followed by visual counting as the most common physical analysis technique. Polymers collected using visual sorting are most frequently identified by spectroscopy (FTIR; Raman). However, destructive analytical techniques (thermal degradation) also provide precise chemical information. In all cases, the methods were screened for advantages, limitations, and fieldwork abilities. This review outlines and critiques knowledge gaps, and recommendations to support standardized and comparable future research.

A Novel Analytical Approach to Assessing Sorption of Trace Organic Compounds into Micro- and Nanoplastic Particles

Assessing the sorption of trace organic compounds (TOrCs) into micro- and nanoplastic particles has traditionally been performed using an aqueous phase analysis or solvent extractions from the particle. Using thermal extraction/desorption–gas chromatography/mass spectrometry (TD-Pyr-GC/MS) offers a possibility to analyze the TOrCs directly from the particle without a long sample preparation. In this study, a combination of two analytical methods is demonstrated. First, the aqueous phase is quantified for TOrC concentrations using Gerstel Twister® and TD-GC/MS. Subsequently, the TOrCs on the particles are analyzed. Different polymer types and sizes (polymethyl methacrylate (PMMA), 48 µm; polyethylene (PE), 48 µm; polystyrene (PS), 41 µm; and PS, 78 nm) were analyzed for three selected TOrCs (phenanthrene, triclosan, and α-cypermethrin). The results revealed that, over a period of 48 h, the highest and fastest sorption occurred for PS 78 nm particles. This was confirmed with a theoretical calculation of the particle surface area. It was also shown for the first time that direct quantification of TOrCs from PS 78 nm nanoparticles is possible. Furthermore, in a mixed solute solution, the three selected TOrCs were sorbed onto the particles simultaneously.

Flow Cytometry as a Rapid Alternative to Quantify Small Microplastics in Environmental Water Samples

The most frequently used method to quantify microplastics (MPs) visually by microscope is time consuming and labour intensive, where the method is also hindered by the size limitation at 10 µm or even higher. A method is proposed to perform pre-concentration of MPs by vacuum filtration, hydrogen peroxide wet digestion, fluorescent staining and flow cytometric determination to rapidly detect and quantify small MPs sized from 1–50 µm. The method performance was evaluated by the spiking of seven different types of polymer, including polystyrene (PS), low-density polyethylene (LDPE), polypropylene (PP), poly(methyl methacrylate) (PMMA), polyvinyl chloride (PVC), polylactic acid (PLA) and acrylonitrile butadiene styrene (ABS) at different levels (400, 4000, 40,000 particles mL−1), with a satisfactory overall % recoveries (101 ± 19.4%) observed, where in general no significant difference between the two methods was observed. Furthermore, a pre-concentration process by vacuum filtration was introduced to reduce the matrix effect. After pre-concentration, satisfactory % recoveries and accuracy in MP counts resulted from both ultrapure water (94.33 ± 11.16%) and sea water (103.17 ± 9.50%) samples. The validated method using flow cytometry can be used to quantify MPs in environmental water samples that can reduce time and human resources.

Toward a Framework for Environmental Fate and Exposure Assessment of Polymers

Development of risk-assessment methodologies for polymers is an emerging regulatory priority to prevent negative environmental impacts; however, the diversity and complexity of polymers require adaptation of existing environmental risk-assessment approaches. The present review discusses the challenges and opportunities for the fate and exposure assessment of polymers in the context of regulatory environmental risk assessment of chemicals. The review discusses the applicability and adequacy for polymers of existing fate parameters used for nonpolymeric compounds and proposes additional parameters that could inform the fate of polymers. The significance of these parameters in various stages of an exposure-assessment framework is highlighted, with classification of polymers as solid or dissolved being key for identification of those parameters most relevant to environmental fate. Considerations to address the key limitations and knowledge gaps are then identified and discussed, specifically the complexity of polymer identification, with the need for characterization of the most significant parameters for polymer grouping and prioritization; the complexity of polymer degradation in the environment, with the need to incorporate the fate and hazards of degradation products into risk assessment; the requirement for development and standardization of analytical methods for characterization of polymer fate properties and degradation products; and the need to develop exposure modeling approaches for polymers. Environ Toxicol Chem 2022;41:515-540. © 2021 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

Emerging investigator series: microplastic sources, fate, toxicity, detection, and interactions with micropollutants in aquatic ecosystems - a review of reviews

Hundreds of review studies have been published focusing on microplastics (MPs) and their environmental impacts. With the microbiota colonization of MPs being firmly established, MPs became an important carrier for contaminants to step inside the food web all the way up to humans. Thus, the continuous feed of MPs into the ecosystem has sparked a multitude of scientific concerns about their toxicity, characterization, and interactions with microorganisms and other contaminants. The reports of common subthemes have agreed about many findings and research gaps but also showed contradictions about others. To unravel these equivocal conflicts, we herein compile all the major findings and analyze the paramount discrepancies among these review papers. Furthermore, we systematically reviewed all the highlights, research gaps, concerns, and future needs. The covered focus areas of MPs' literature include the sources, occurrence, fate, existence, and removal in wastewater treatment plants (WWTPs), toxicity, interaction with microbiota, sampling, characterization, data quality, and interaction with other co-contaminants. This study reveals that many mechanisms of MPs' behavior in aquatic environments like degradation and interaction with microbiota are yet to be comprehended. Furthermore, we emphasize the critical need to standardize methods and parameters for MP characterization to improve the comparability and reproducibility of the incoming research.

Occurrence, toxicity and remediation of polyethylene terephthalate plastics. A review

Polyethylene terephthalate is a common plastic in many products such as viscose rayon for clothing, and packaging material in the food and beverage industries. Polyethylene terephthalate has beneficial properties such as light weight, high tensile strength, transparency and gas barrier. Nonetheless, there is actually increasing concern about plastic pollution and toxicity. Here we review the properties, occurrence, toxicity, remediation and analysis of polyethylene terephthalate as macroplastic, mesoplastic, microplastic and nanoplastic. Polyethylene terephthalate occurs in groundwater, drinking water, soils and sediments. Plastic uptake by humans induces diseases such as reducing migration and proliferation of human mesenchymal stem cells of bone marrow and endothelial progenitor cells. Polyethylene terephthalate can be degraded by physical, chemical and biological methods.

Microplastics and nanoplastics science: collecting and characterizing airborne microplastics in fine particulate matter

Microplastic (MP) pollution in the environment is increasing, leading to growing concerns about human exposures and the subsequent impact on health. Although marine MP research has received significant attention in recent years, only a few studies have attempted characterization of MP in air and examined the MP uptake and influence via inhalation on human health. Moreover, the methods used for MP characterization in the marine environment require further optimization to be applicable to MP in the air. This paper details method for collecting and characterizing MP < 2.5 μm in air samples for the purposes of toxicological assessment. The first phase of the study evaluated (a) the suitability of various filter types to collect respirable airborne MP <2.5 μm, and; (b) the ability of Raman and enhanced darkfield-hyperspectral spectroscopy methods to identify MP reference standards collected from spiked filters and in cells after exposure to reference MP. In the second phase, these methods were employed to characterize MP <2.5 μm in personal, indoor and outdoor filter air samples and in cells following exposure to filter extracted material. The results showed the presence of a variety of MP in the respirable size fraction (0.1-1 µm aerodynamic diameter). Silver membrane filters were found not suitable for collecting and analyzing MP <2.5 μm. While it was easy to detect reference MP in cells post-exposure, the identity of only two types of air-borne MP was confirmed in cells. The study highlighted possible sources of artifacts and inconsistencies in analyzing airborne MP.

How fast, how far: Diversification and adoption of novel methods in aquatic microplastic monitoring

Since 2004, there has been a marked diversification in the methods used to determine aquatic microplastic (MP) concentrations. Despite calls for a unified approach to MP sampling, the proliferation of new methods has accelerated in recent years. Both minor method adaptations and entirely novel approaches have been introduced to overcome barriers to reliable MP sampling, extraction and quantification, resulting in a variety of complimentary but also competing approaches. However, there is little clarity regarding the extent to which new methods are acknowledged and adopted, or of the apparent drivers of, as well as barriers to, said adoption. To explore these issues, the rate of method diversification was examined in a systematic review. The rate and degree of diversification were determined by scoring each method by its "degree of novelty": highly novel methods, secondary adaptations of existing methods and smaller, tertiary adaptations of existing methods. This analysis revealed that the rate of method diversification has been greatest since 2011. Our results indicate limited use of these novel methods and adaptations in the subsequent literature, with many researchers falling back on methods that are well established in the existing literature. Importantly, there is little consistency in the units used when reporting MP concentrations. However, these differences are seldom driven by method selection and are rather the result of discrepancies between researchers. Thus, in understanding the requirements of comparability and consistent reporting for monitoring purposes, we can apply a diverse approach to sampling whilst maintaining the applicability and usefulness of the resulting data.

Science-society-policy interface for microplastic and nanoplastic: Environmental and biomedical aspects

The global concern over the possible consequences of the downsizing of plastic to microplastics (MPs) and nano plastics (NPs) needs to be addressed with a new conceptual framework. The transformation of plastics to MPs and NPs can be discussed in terms of fundamental physics principles applicable to micro and nanophase matter and colloidal science principles. Further, accurate and reliable detection and characterization of MPs and NPs are crucial for an extensive understanding of their environmental and ecological impacts. The other decisive factor that can classify MPs and NPs as hazardous to existing nanomaterials is discussing the cytotoxicity study on human cell lines. The human health risk assessment that might arise from the ingestion of MPs and NPs can be addressed about contrast agents used for medical imaging. However, the lack of standard analytical techniques for MPs and NPs measurement is an emerging challenge for analytical scientists due to their complex physicochemical properties, especially in environmental samples. This review article navigates readers through the point of origin of MPs and NPs and their interdisciplinary aspects. Biomedical applications of plastics and concerns over the toxicity of MPs and NPs are further analyzed. Moreover, the analytical challenges of MPs and NPs have been discussed with critical inputs. Finally, the worldwide efforts being made for creating a common platform of discussion on a different aspect of plastic pollution were taken into account.

Extraction and identification methods of microplastics and nanoplastics in agricultural soil: A review

As the abundance of microplastics and nanoplastics (MPs/NPs) increases in the environment, their presence in agricultural soil has become of interest. MPs/NPs can affect soil physical and chemical properties and be absorbed by plants and soil animals, causing physical and chemical damage. Soil MPs exceeding a certain concentration cause significant harm. Therefore, the extraction and identification of MPs in soil are vital for determining soil pollution. However, soils contain many other particles of similar size to MPs/NPs, making it more difficult to distinguish them than in water bodies. No standardized extraction and identification method is available to quantify MPs/NPs in soil. Various methods have been described in the literature, but they involve many different procedures for sampling, purification, digestion, and identification. This paper reviews extraction and identification methods for MPs/NPs in soil, sediment, and water and summarizes agricultural soil sampling and preservation, MPs/NPs separation, organic matter removal, and MPs/NPs identification. We also compare the advantages and disadvantages of existing methods and propose future research topics.

A comprehensive review on assessment of plastic debris in aquatic environment and its prevalence in fishes and other aquatic animals in India

The presence of meso, macro, and microplastics (MPs) in aquatic environments has raised concerns due to their potential risks to aquatic as well as human life. Though plastics are considered to be inert in nature, MPs with toxic additives and accumulated contaminants have harmful ecological effects. Reports of absorption of MPs by internal tissues and toxicity in vital organs such as lung cells, liver, and brain cells have proved its serious health hazards. The study of plastic debris in the aquatic environment deserves special attention due to its ecotoxicological impact. This review presents a detailed account of the assessment of plastic debris in marine as well as freshwater environments. The formation of MPs and their sources, sampling, isolation, identification and characterization methods adopted, and the prevalence of MPs in aquatic life are discussed. To the best of our knowledge, the present article is a first-ever comprehensive review covering the entire of India. Our review finds that, so far, very few studies have been carried out, and there is a paucity of information, especially on the prevalence of plastic debris in the freshwater environment, fish, and other aquatic animals in India. While major studies have been done at various coastal locations in the southern part of India and a few studies in the rest of India, south-eastern states remain neglected. Toxicological studies on various life forms, including humans, are lacking. The present review also fills the gap in our knowledge of the various locations studied across India and can guide future research.

Method for extraction of nanoscale plastic debris from soil

Sample preparation for extraction of nanoscale plastic debris (NPD, size < 1 μm) from environmental samples is a critical step to prepare NPD for further identification and quantification. Developing a NPD extraction method from soil matrices is particularly challenging due to the complexity of solid matrices. In the present study, we built upon the lessons learned from method development for extraction of microplastics and nanomaterials from environmental samples to develop a sample preparation method for extraction of NPD from soil matrices. The evaluation criteria for the extraction method are size distribution, particle number recovery, and particle mass recovery. Since there is no validated method available to trace and quantify the mass of NPD in complex matrices, we applied polystyrene particles doped with europium (Eu-PS NPs). Standard LUFA soil and field soil were spiked and mixed for 24 h with 1 mg of Eu-PS NPs and the particles were extracted from the matrices of the soils. The extraction method did not significantly influence the size distribution of the particles and the extraction agents did not degrade the Eu-PS NPs. Mass balance calculation suggested recoveries of 82 and 77% of the added Eu-PS NPs in LUFA soil and field soil, respectively. The number recoveries of the particles were 81 and 85% for LUFA soil and field soil, respectively. This method can be further optimized and used as the first building block to develop a generic sample preparation method for the extraction of NPD from soil samples. By combining this developed and verified extraction method with identification and quantification techniques, a fit-for-purpose workflow can be developed to quantify and subsequently understand the fate of NPD in soil.

Microplastics in the Aquatic Environment: Occurrence, Persistence, Analysis, and Human Exposure

Microplastics (MP) have recently been considered as emerging contaminants in the water environment. In the last number of years, the number of studies on MP has grown quickly due to the increasing consciousness of the potential risks for human health related to MP exposure. The present review article discusses scientific literature regarding MP occurrence and accumulation on the aquatic compartment (river, lake, wastewater, seafood), the analytical methods used to assess their concentration, their fate and transport to humans, and delineates the urgent areas for future research. To better analogize literature data regarding MP occurrence in the aquatic compartment we subdivided papers based on sampling, analytical methods, and concentration units with the aim to help the reader identify the similarities and differences of the considered research papers, thus making the comparison of literature data easier and the individuation of the most relevant articles for the reader’s interests faster. Furthermore, we argued about several ways for MP transport to humans, highlighting some gaps in analytical methods based on the reviewed publications. We suggest improving studies on developing standardized protocols to collect, process, and analyze samples.

Plastic particles in soil: state of the knowledge on sources, occurrence and distribution, analytical methods and ecological impacts

Increased production and use of plastics has resulted in growth in the amount of plastic debris accumulating in the environment, potentially fragmenting into smaller pieces. Fragments <5 mm are typically defined as microplastics, while fragments <0.1 μm are defined as nanoplastics. Over the past decade, an increasing number of studies have reported the occurrence and potential hazards of plastic particles in the aquatic environment. However, less is understood about plastic particles in the terrestrial environment and specifically how much plastic accumulates in soils, the possible sources, potential ecological impacts, interaction of plastic particles with the soil environment, and appropriate extraction and analytical techniques for assessing the above. In this review, a comprehensive overview and a critical perspective on the current state of knowledge on plastic pollution in the soil environment is provided: detailing known sources, occurrence and distribution, analytical techniques used for identification and quantification and the ecological impacts of particles on soil. In addition, knowledge gaps are identified along with suggestions for future research.

Organic Contaminants and Interactions with Micro- and Nano-Plastics in the Aqueous Environment: Review of Analytical Methods

Micro- and nanoplastic particles are increasingly seen not only as contaminants themselves, but also as potential vectors for trace organic chemicals (TOrCs) that might sorb onto these particles. An analysis of the sorbed TOrCs can either be performed directly from the particle or TOrCs can be extracted from the particle with a solvent. Another possibility is to analyze the remaining concentration in the aqueous phase by a differential approach. In this review, the focus is on analytical methods that are suitable for identifying and quantifying sorbed TOrCs on micro- and nano-plastics. Specific gas chromatography (GC), liquid chromatography (LC) and ultraviolet-visible spectroscopy (UV-VIS) methods are considered. The respective advantages of each method are explained in detail. In addition, influencing factors for sorption in the first place are being discussed including particle size and shape (especially micro and nanoparticles) and the type of polymer, as well as methods for determining sorption kinetics. Since the particles are not present in the environment in a virgin state, the influence of aging on sorption is also considered.

A systematic protocol of microplastics analysis from their identification to quantification in water environment: A comprehensive review

With microplastics (MPs) being detected in aquatic environments, numerous studies revealed that they caused severe environmental issues, including damage to ecosystems and human health. MPs transport persistent organic pollutants by adsorbing them, and in nanoplastics this phenomenon is exacerbated by increased surface area. Despite their environmental risk, systematic protocol for qualitative and quantitative analysis are yet to be established in environmental analytical chemistry. Current analytical technologies on MP identification have technological limits with regard to detecting small sized particles (<1 µm), underestimation of MPs with organic contaminants, and physico-chemically altered particles by weathering and photo degradation. According to the published works, MPs are spread in living organisms through the food web, and are even detected in bottled water. To determine its eco-toxicity and removal by biodegradation, its accuracy, reliability, and reproducibility should be ensured by establishing a systematic protocol of MP identification. This review compares procedures, applicability, and limitations of Fourier transform infrared spectroscopy, Raman spectroscopy, and thermo-analytical methods for identifying MPs. Finally, it suggests systematic protocols for MPs analysis.

Microplastics in Mediterranean Coastal Countries: A Recent Overview

The aim of this paper is to present information gathered from studies regarding the current status and challenges of microplastics (MPs) in Mediterranean coastal counties. MPs are considered emerging pollutants, and their effect on fish and on the final consumer through the trophic food chain are of great concern. Studies from almost all of the Mediterranean coastal countries are gathered and discussed. The source of MPs, as well as their transfer and accumulation are reviewed. In addition, the laboratory techniques for sampling, analysis and characterization of MPs are presented. Moreover, the current regulations for MPs restrictions in Europe will be discussed. Finally, the authors present the current challenges on the topic and provide recommendations for future work.

A critical review of the overlooked challenge of determining micro-bioplastics in soil

Currently, non-biodegradable oil-based plastics are gradually being replaced by bio-based biodegradable plastics to prevent the formation of microplastics. For biodegradable materials to decompose completely, however, they require specific conditions that are rarely met in ecosystems. Paradoxically, this may lead to the fast production of microplastics from biodegradable materials, i.e. micro-bioplastics. Until recently, the scientific focus has been solely on the estimation of conventional microplastics. As a result, there is a lack of analytical methods for determining the amount of micro-bioplastics in soil. In this review, we address this problem by summarising sample pre-treatments and analytical techniques suitable for the determination of conventional microplastics, which serve as inspiration for the determination of micro-bioplastics from polyhydroxybutyrates, polylactic acid and polybutylene adipate terephthalate in soil. The analytical techniques include both pyrolysis-based techniques, i.e. thermoanalytical and non-thermoanalytical approaches including sample pre-separation and respective detection limits. We conclude that due to the incomplete knowledge of the production rate of micro-bioplastics, fate, sorption properties and toxicity, it is necessary to develop and validate a rapid and suitable method for their determination. Indeed, the use of thermoanalytical approaches seems to be the most promising strategy. Furthermore, we suggest how the development and analysis of micro-bioplastics should be addressed in future research.

Microplastics in waters and soils: Occurrence, analytical methods and ecotoxicological effects

Microplastics (MPs) are ubiquitous in the environment and more abundant in the marine environment. Consequently, increasing focus has been put on MPs in oceans and seas, while little importance has been attached to their presence in freshwaters and soils. Therefore, this paper aimed to provide a comprehensive review of the occurrence, analysis and ecotoxicology of MPs. The abundance and distribution of MPs in several typical freshwater systems of China were summarized. It suggested that the surface water of Poyang Lake contained the highest concentration of 34 items/L MPs among all the 8 freshwater systems, and the content of MPs in sediments were higher than that of the surface water. Net-based zooplankton sampling methods are the most frequently utilized sampling methods for MPs, and density separation, elutriation and digestion are three major pretreatment methods. Fourier transform infrared spectroscopy, Raman spectroscopy and pyrolysis-gas chromatography coupled to mass spectrometry are often used to identify the polymer types of MPs. Besides, MPs might damage the digestive tract of various organisms and negatively inhibit their growth, feeding and reproduction. The ways of human exposure to MPs are by ingestion, inhalation and dermal exposure, digestive and respiratory system might be adversely influenced. However, potential health risks of MPs to humans are remained insufficiently researched. Overall, by showing the presence of MPs in freshwaters and soils as well as possible ecotoxicological effects on the environment and humans, this paper provided a framework for future research in this field.

Microplastics and Nanoplastics in the Freshwater and Terrestrial Environment: A Review

This review is a critical analysis of current freshwater and terrestrial research with an emphasis on transport, behaviour, fate and subsequent ecological impacts that plastic pollution poses. The current methods of extraction and evaluation of organic-rich samples are also explored for both micro- and nanoplastics. Furthermore, micro- and nanoplastics are discussed with reference to their environmental and health implications for biota. Regulations imposed on the manufacture and distribution of plastics globally are also noted. Within the review, the current literature has been presented and knowledge gaps identified. These include the characterization and quantification of micro- and nanoplastics entering and forming within the freshwater and terrestrial environment, the fate and behaviour of micro- and nanoplastics under varying conditions and the impacts of micro- and nanoplastics on freshwater and terrestrial ecosystems.

High-Throughput Analyses of Microplastic Samples Using Fourier Transform Infrared and Raman Spectrometry

Determining microplastics in environmental samples quickly and reliably is a challenging task. With a largely automated combination of optical particle analysis, Fourier transform infrared (FT-IR), and Raman microscopy along with spectral database search, particle sizes, particle size distributions, and the type of polymer including particle color can be determined. We present a self-developed, open-source software package for realizing a particle analysis approach with both Raman and FT-IR microspectroscopy. Our software GEPARD (Gepard Enabled PARticle Detection) allows for acquiring an optical image, then detects particles and uses this information to steer the spectroscopic measurement. This ultimately results in a multitude of possibilities for efficiently reviewing, correcting, and reporting all obtained results.

A Practical Overview of Methodologies for Sampling and Analysis of Microplastics in Riverine Environments

Microplastics have recently been stated as being remarkable contaminants of all environmental matrices. The lack of consistent and standardised methods and protocols used to evaluate and quantify microplastics present in riverine systems made a comparison among different studies a critical issue. Based on literature research and the practical expertise of the authors, this work presents a complete collection and analysis of procedures concerning the monitoring of microplastics in riverine environments, focusing on their sampling and analytical protocols to identify, quantify, and characterise them. Further details regarding the advantages and disadvantages of each analytical technique described, such as general recommendations and suggestions, are provided to give practical support for analytical procedures. In particular, microplastics studies consist firstly of their sampling from the aquatic compartment (aqueous and solid phase). Based on the goal of the research, specific devices can be used to collect particles from different matrices. It follows their quantification after extraction from the environmental matrix, adopting different protocols to isolate microplastics from a large amount of organic matter present in a riverine system. In the end, additional qualitative analyses (e.g., RAMAN and FTIR spectroscopy, GC-MS) are required to identify the chemical composition of particles for a better image regarding the abundance of polymer types, their origin, or other information related to manufacturing processes.

Analytical methods and environmental processes of nanoplastics

The degradation of plastic debris may result in the generation of nanoplastics (NPs). Their high specific surface area for the sorption of organic pollutions and toxic heavy metals and possible transfer between organisms at different nutrient levels make the study of NPs an urgent priority. However, there is very limited understanding on the occurrence, distribution, abundant, and fate of NPs in the environment, partially due to the lack of suitable techniques for the separation and identification of NPs from complex environmental matrices. In this review, we first overviewed the state-of-the-art methods for the extraction, separation, identification and quantification of NPs in the environment. Some of them have been successfully applied for the field determination of NPs, while some are borrowed from the detection of microplastics or engineered nanomaterials. Then the possible fate and transport of NPs in the environment are thoroughly described. Although great efforts have been made during the recent years, large knowledge gaps still exist, such as the relatively high detection limit of existing method failing to detect ultralow masses of NPs in the environment, and spherical polystyrene NP models failing to represent the various compositions of NPs with different irregular shapes, which needs further investigation.

Assessment of microplastics in freshwater systems: A review

The reliance on plastic for a vast number of consumer products, many of them single-use, results in their continuous entry into aquatic environments. Plastic waste can fragment into smaller debris, some with a diameter < 5 mm (microplastics). Microplastics are of growing concern especially since 2014, however to date research on microplastic pollution has mainly focused on marine environments, partly because it has been mistakenly thought that sewage treatment plants could remove all plastic debris. To understand the impact of microplastic pollution in freshwater environments, an assessment of research on the sources, distribution and effects of microplastics, and trends in their analysis and policy has been carried out. Main sources of microplastic found in freshwater environments include synthetic textiles, personal care products, industrial raw materials and the improper disposal of plastic waste. Microplastic pollution is a global issue that presents with a broad range of concentration: for example, 3.5 × 10^³ microplastic units·L^-1 were reported in sediment of Lake Huron, in the US and as low as 1.2×10^-4 units·L^-1 in countries with sparse population such as Mongolia. The main polymer constituents of microplastics found in freshwaters have been identified as polyethylene (PE), polypropylene (PP), polystyrene (PS), and polyethylene terephthalate (PET), accounting for 70% of the total, each with a very similar frequency of occurrence. Despite microplastics being relatively inert, they are found to cause some effects in aquatic organisms. Future work should focus on monitoring microplastic pollution in regions from where there is currently scarce published data (e.g. South America, Africa and North Asia) and the study of their sources, stability, transport and effects to freshwater ecosystems. The establishment of standardized monitoring methods will allow for the comparison of data from different geographic areas. This information will inform measures to reduce the release and occurrence of microplastics in aquatic environments.

An overview of microplastics characterization by thermal analysis

Microplastics may be present in the environment as primary microplastics (manufactured) or secondary microplastics (result of the continuous degradation of larger plastic pieces into smaller fragments due to environmental, physicochemical and biotic factors). To fully understand the dynamics of microplastic particles and their environmental effects, harmonized, automated, cheap, rapid and reliable methodologies for sampling, extraction and characterization of microplastic need to be developed. This review focuses on the potential of thermal analytical techniques for microplastics characterization and highlights some of the new trends in this area.

Wastewater treatment plant as microplastics release source - Quantification and identification techniques

The high presence of microplastics (MPs) in different sizes, materials and concentrations in the aquatic environment is a global concern due to their potential physically and chemically harm to aquatic organisms including mammals. Furthermore, the bioaccumulation of these compounds is leading to their ingestion by humans through the consumption of sea food and even through the terrestrial food chain. Even though conventional wastewater treatment plants are capable of eliminating more than 90% of the influent MPs, these systems are still the main source of MPs introduction in the environment due to the high volumes of effluents generated and returned to the environment. The amount of MPs dumped by WWTP is influenced by the configuration of the WWTP, population served and influent flow. Thus, the average of MP/L disposed vary widely depending on the region. In addition to MPs disposed in water bodies, more than 80% of these emerging contaminants, which enter the WWTP, are retained in biosolids that can be applied as fertilizers, representing a potential source of soil contamination. Due to the continuous disposal of MPs in the environment by effluent treatment systems and their polluting potential, separation and identification techniques have been assessed by several researchers, but unfortunately, there are no standard protocols for them. Aiming to provide insight about the relevance of studying the WWTP as source of MPs, this review summarizes the currently methodologies used to classify and identify them.

Trace analysis of polystyrene microplastics in natural waters

The development of quantitative and qualitative analytical methods to assess micro-plastics (MPLs) and nano-plastics (NPLs) content in the environment is a central issue for realistic risk assessment studies. However, the quantitative analysis continues being a critical issue, in particular for MPLs from 100 μm down to the nano-sized range in complex environmental samples. This paper evaluates the potential of mass spectrometry for the analysis of MPLs and NPLs. The performance of different techniques including matrix-assisted laser desorption ionisation (MALDI) coupled to time-of-flight mass spectrometry (TOF-MS), liquid chromatography coupled to high-resolution mass spectrometry (LC-HRMS), and the ambient ionisation approaches as desorption electrospray ionisation (DESI) and direct analysis real-time (DART), were assessed for the study of polystyrene (PS) MPLs and NPLs in natural waters. A method based on LC-HRMS, equipped with an atmospheric pressure photoionisation source (APPI), operated in negative conditions for the quantitative analysis of PS MPLs and NPLs in natural waters, was developed. The chromatographic separation was achieved using an advanced polymer chromatographic (APC) column using toluene isocratic as the mobile phase. The optimal analytical method showed an instrumental limit of detection (ILOD) of 20 pg and methods limits of detection and quantification around 30 pg L^-1 and 100 pg L^-1, respectively. And, recoveries of 60 and 70% in samples from rivers and the marine coast, respectively. The performance of the new method was proved by the analysis of fortified samples and natural seawater samples.

Application of FTIR Method for the Assessment of Immobilization of Active Substances in the Matrix of Biomedical Materials

Background: The purpose of the study was to demonstrate the usefulness of the Fourier transform infrared spectroscopy (FTIR) method for the evaluation of the modification process of biomaterials with the participation of active substances. Methods: Modified catheter samples were prepared by activating the matrix with an acid, iodine, or bromine, and then immobilizing the active molecules. To carry out the modification process, the Fourier transform infrared-attenuated total reflectance (FTIR-ATR) method was used. Results: FTIR analysis indicated the presence of the immobilized substances in the catheter matrix and site-specific reactions. Conclusion: We surmise that the infrared spectroscopic technique is an ideal tool for the assessment of the drug immobilization and the changes occurring in the course of the modification process.

Modeling Solid State Stability for Speciation: A Ten-Year Long Study

Speciation studies are based on fundamental models that relate the properties of biomimetic coordination compounds to the stability of the complexes. In addition to the classic approach based on solution studies, solid state properties have been recently proposed as supporting tools to understand the bioavailability of the involved metal. A ten-year long systematic study of several different complexes of imidazole substituted ligands with transition metal ions led our group to the definition of a model based on experimental evidences. This model revealed to be a useful tool to predict the stability of such coordination complexes and is based on the induced behavior under thermal stress. Several different solid state complexes were characterized by Thermally Induced Evolved Gas Analysis by Mass Spectrometry (TI-EGA-MS). This hyphenated technique provides fundamental information to determine the solid state properties and to create a model that relates stability to coordination. In this research, the model resulting from our ten-year long systematic study of complexes of transition metal ions with imidazole substituted ligands is described. In view of a systematic addition of information, new complexes of Cu(II), Zn(II), or Cd(II) with 2-propyl-4,5-imidazoledicarboxylic acid were precipitated, characterized, and studied by means of Thermally Induced Evolved Gas Analysis performed by mass spectrometry (TI-EGA-MS). The hyphenated approach was applied to enrich the information related to thermally induced steps, to confirm the supposed decomposition mechanism, and to determine the thermal stability of the studied complexes. Results, again, allowed supporting the theory that only two main characteristic and common thermally induced decomposition behaviors join the imidazole substituted complexes studied by our group. These two behaviors could be considered as typical trends and the model allowed to predict coordination behavior and to provide speciation information.

Characterization of microplastics in environment by thermal gravimetric analysis coupled with Fourier transform infrared spectroscopy

As a global pollutant, microplastics have attracted attention from the public and researchers. However, the lack of standard and time-saving methods for analysis has become one of the bottlenecks in microplastics research. Here, we demonstrate TGA coupled to FTIR to identify and quantify certain microplastics in environment. Samples were pyrolyzed in TGA and the pyrolysis gases were analyzed by FTIR. Combining TGA and FTIR data adds discriminatory power as temperature profiles and absorption spectra differ among several common plastics. To quantify on a mass basis, we calibrated on characteristic IR peaks at temperatures of maximum weight loss for individual polymers. The method can distinguish PVC, PS and was validated by spiking samples with known quantities of microplastics. The result of field sample experiments showed that TGA-FTIR can be used to identify and quantify PVC and PS in bivalves, seawater and soil. And the method may be applicable to environmental samples.

Introducing a soil universal model method (SUMM) and its application for qualitative and quantitative determination of poly(ethylene), poly(styrene), poly(vinyl chloride) and poly(ethylene terephthalate) microplastics in a model soil

Methods for analysis of microplastic in soils are still being developed. In this study, we evaluated the potential of a soil universal model method (SUMM) based on thermogravimetry (TGA) for the identification and quantification of microplastics in standard loamy sand. Blank and spiked soils (with amounts of one of four microplastic types) were analyzed by TGA. For each sample, thermal mass losses (TML) in 10 °C intervals were extracted and used for further analysis. To explain and demonstrate the principles of SUMM, two scenarios were discussed. The first refers to a rare situation in which an uncontaminated blank of investigated soil is available and TML of spiked and blank soils are subtracted. The results showed that the investigated microplastics degraded in characteristic temperature areas and differences between spiked and blank soils were proportional to the microplastics concentrations. The second scenario reflects the more common situation where the blank is not available and needs to be replaced by the previously developed interrelationships representing soil universal models. The models were consequently subtracted from measured TML. Sparse principal component analysis (sPCA) identified 8 of 14 modeled differences between measured TMLs and the universal model as meaningful for microplastics discrimination. Calibrating various microplastics concentrations with the first principal component extracted from sPCA resulted in linear fits and limits of detection in between environmentally relevant microplastics concentrations. Even if such an approach using calculated standards still has limitations, the SUMM shows a certain potential for a fast pre-screening method for analysis of microplastics in soils.

Separation and Analysis of Microplastics and Nanoplastics in Complex Environmental Samples

The vast amount of plastic waste emitted into the environment and the increasing concern of potential harm to wildlife has made microplastic and nanoplastic pollution a growing environmental concern. Plastic pollution has the potential to cause both physical and chemical harm to wildlife directly or via sorption, concentration, and transfer of other environmental contaminants to the wildlife that ingest plastic. Small particles of plastic pollution, termed microplastics (>100 nm and <5 mm) or nanoplastics (<100 nm), can form through fragmentation of larger pieces of plastic. These small particles are especially concerning because of their high specific surface area for sorption of contaminants as well as their potential to translocate in the bodies of organisms. These same small particles are challenging to separate and identify in environmental samples because their size makes handling and observation difficult. As a result, our understanding of the environmental prevalence of nanoplastics and microplastics is limited. Generally, the smaller the size of the plastic particle, the more difficult it is to separate from environmental samples. Currently employed passive density and size separation techniques to isolate plastics from environmental samples are not well suited to separate microplastics and nanoplastics. Passive flotation is hindered by the low buoyancy of small particles as well as the difficulty of handling small particles on the surface of flotation media. Here we suggest exploring alternative techniques borrowed from other fields of research to improve separation of the smallest plastic particles. These techniques include adapting active density separation (centrifugation) from cell biology and taking advantage of surface-interaction-based separations from analytical chemistry. Furthermore, plastic pollution is often challenging to quantify in complex matrices such as biological tissues and wastewater. Biological and wastewater samples are important matrices that represent key points in the fate and sources of plastic pollution, respectively. In both kinds of samples, protocols need to be optimized to increase throughput, reduce contamination potential, and avoid destruction of plastics during sample processing. To this end, we recommend adapting digestion protocols to match the expected composition of the nonplastic material as well as taking measures to reduce and account for contamination. Once separated, plastics in an environmental sample should ideally be characterized both visually and chemically. With existing techniques, microplastics and nanoplastics are difficult to characterize or even detect. Their low mass and small size provide limited signal for visual, vibrational spectroscopic, and mass spectrometric analyses. Each of these techniques involves trade-offs in throughput, spatial resolution, and sensitivity. To accurately identify and completely quantify microplastics and nanoplastics in environmental samples, multiple analytical techniques applied in tandem are likely to be required.

Automated thermal extraction-desorption gas chromatography mass spectrometry: A multifunctional tool for comprehensive characterization of polymers and their degradation products

The TED-GC-MS analysis is a two-step method. A sample is first decomposed in a thermogravimetric analyzer (TGA) and the gaseous decomposition products are then trapped on a solid-phase adsorber. Subsequently, the solid-phase adsorber is analyzed with thermal desorption gas chromatography mass spectrometry (TDU-GC-MS). This method is ideally suited for the analysis of polymers and their degradation processes. Here, a new entirely automated system is introduced which enables high sample throughput and reproducible automated fractioned collection of decomposition products. The fractionated collection together with low temperatures reduces the risk of contamination, improves instrumental stability and minimizes maintenance efforts. Through variation of the two main parameters (purge gas flow and heating rate) it is shown how the extraction process can be optimized. By measuring the decomposition products of polyethylene it is demonstrated that compounds with masses of up to 434 Da can be detected. This is achieved despite the low temperature (˜40 °C) of the solid-phase adsorber and the low thermal desorption temperature of 200 °C in the TDU unit. It is now shown that automated TED-GC-MS represents a new flexible multi-functional method for comprehensive polymer analyses. Comparable polymer characterization was previously only achievable through a combination of multiple independent analytical methods. This is demonstrated by three examples focused on practical challenges in materials analysis and identification: The first one is the analysis of wood plastic composites for which the decomposition processes of the polymer and the bio polymer (wood) could be clearly distinguished by fractionated collection using sequential adsorbers. Secondly, a fast quantitative application is shown by determining the weight concentrations of an unknown polyolefin blend through comparison with a reference material. Additionally, the determination of microplastic concentrations in environmental samples is becoming an increasingly important analytical necessity. It is demonstrated that with TED-GC-MS calibration curves showing good linearity for the most important precursors for microplastic, even complex matrix materials (suspended particulate matter) can be successfully analyzed.

Role of extracellular polymeric substances in the acute inhibition of activated sludge by polystyrene nanoparticles

Microplastics and nanoplastics in aquatic systems have become a global concern because of their persistence and adverse consequences to ecosystems and potentially human health. Though wastewater treatment plants (WWTPs) are considered a potential source of microplastics in the environment, the role of extracellular polymeric substances (EPS) of activated sludge on the fate of nanoplastics is not clear. In this study, the role of EPS in the influence of polystyrene nanoparticles (PS-NPs) on the endogenous respiration of activated sludge was investigated for the first time. The results showed that the acute inhibition of activated sludge by PS-NPs was enhanced with increasing PS-NPs concentration. X-ray photoelectron spectroscopy (XPS) results indicate that the functional groups involved in the interactions between PS-NPs and EPS were carbonyl and amide groups and the side chains of lipids or amino acids. Furthermore, the Fourier transform infrared (FTIR) spectroscopy results show that the protein secondary structures in EPS were changed by PS-NPs and lead to the bioflocculation of activated sludge, which provides a better understanding on the fate of nanoplastics in WWTPs.

Microplastics in freshwater systems: A review on occurrence, environmental effects, and methods for microplastics detection

The continuous increase in synthetic plastic production and poor management in plastic waste have led to a tremendous increase in the dumping into our aqueous environment. Consequently, microplastics commonly defined as sizes less than 5 mm are produced and stay in both seawater and freshwater environment. The presence of microplastics as a new type of emerging contaminant has become a great issue of concerns from public and government authorities. The sources of microplastics to freshwater systems are many with the largest portion from wastewater treatment plants. The abundance of microplastics varies with the location, from above 1 million pieces per cubic meter to less than 1 piece in 100 cubic meters. Microplastics can cause several harmful physical effects on humans and living organisms through such mechanisms as entanglement and ingestion. The microplastics can act as carriers of various toxins such as additives from industrial production processes and persistent contaminants by the sorption in waters. Those toxins may cause great health problems to humans. A few studies on the fishes demonstrated that the microplastics and the associated toxins are bio-accumulated and cause such problems as intestinal damage and change in metabolic profiles. In studies of microplastics, fresh water is first sampled by the nets with typical mesh size of 330 μm for collection of microplastics. After the volume reducing process, the samples will then go through the purification process including density separation by such inorganic salts as sodium chloride and digestion process by oxidizing agents or enzymes. The sequence of these two processes (namely purification and digestion) is dependent on the sample type. The purified samples can be studied by several analytical methods. The commonly used methods for the qualification studies are FTIR spectroscopy, Raman spectroscopy, pyrolysis-GC/MS, and liquid chromatography. A tagging method can be used in the quantification study. Our literature study finds that there is still no universal accepted quantification and qualification tools of microplastics in fresh waters. More work is anticipated so as to obtain accurate information on microplastics in freshwater, which can then be used for the better assessment of the environmental risk.

Comparison of different methods for MP detection: What can we learn from them, and why asking the right question before measurements matters?

In recent years, an increasing trend towards investigating and monitoring the contamination of the environment by microplastics (MP) (plastic pieces < 5 mm) has been observed worldwide. Nonetheless, a reliable methodology that would facilitate and automate the monitoring of MP is still lacking. With the goal of selecting practical and standardized methods, and considering the challenges in microplastics detection, we present here a critical evaluation of two vibrational spectroscopies, Raman and Fourier transform infrared (FTIR) spectroscopy, and two extraction methods: thermal extraction desorption gas chromatography mass spectrometry (TED-GC-MS) and liquid extraction with subsequent size exclusion chromatography (SEC) using a soil with known contents of PE, PP, PS and PET as reference material. The obtained results were compared in terms of measurement time, technique handling, detection limits and requirements for sample preparation. The results showed that in designing and selecting the right methodology, the scientific question that determines what needs to be understood is significant, and should be considered carefully prior to analysis. Depending on whether the object of interest is quantification of the MP particles in the sample, or merely a quick estimate of sample contamination with plastics, the appropriate method must be selected. To obtain overall information about MP in environmental samples, the combination of several parallel approaches should be considered.

Fast identification of microplastics in complex environmental samples by a thermal degradation method

In order to determine the relevance of microplastic particles in various environmental media, comprehensive investigations are needed. However, no analytical method exists for fast identification and quantification. At present, optical spectroscopy methods like IR and RAMAN imaging are used. Due to their time consuming procedures and uncertain extrapolation, reliable monitoring is difficult. For analyzing polymers Py-GC-MS is a standard method. However, due to a limited sample amount of about 0.5 mg it is not suited for analysis of complex sample mixtures like environmental samples. Therefore, we developed a new thermoanalytical method as a first step for identifying microplastics in environmental samples. A sample amount of about 20 mg, which assures the homogeneity of the sample, is subjected to complete thermal decomposition. The specific degradation products of the respective polymer are adsorbed on a solid-phase adsorber and subsequently analyzed by thermal desorption gas chromatography mass spectrometry. For certain identification, the specific degradation products for the respective polymer were selected first. Afterwards real environmental samples from the aquatic (three different rivers) and the terrestrial (bio gas plant) systems were screened for microplastics. Mainly polypropylene (PP), polyethylene (PE) and polystyrene (PS) were identified for the samples from the bio gas plant and PE and PS from the rivers. However, this was only the first step and quantification measurements will follow.