Key Points:
- Microplastics (MPs) vary widely in size, shape, and polymer type, and are highly prone to contamination. Tailored sample preparation protocols are essential for different matrices (water, sediments, tissues, air) to avoid false positives and ensure accurate identification.
- Py-GC–MS is the leading analytical technique for polymer identification. While liquid chromatography is less commonly used for detecting MPs directly, it plays a valuable role in analyzing associated additives and degradation products.
- Emerging studies have identified MPs in human placenta, blood, lungs, and even brain tissue. These findings highlight the potential for bioaccumulation and long-term health impacts, emphasizing the urgent need for standardized detection methods and further toxicological research.
Microplastics (MPs)—those tiny plastic particles less than 5 mm in size—continue to be a prominent topic both in the media and within scientific research.
Ubiquitous in marine, freshwater, terrestrial, and atmospheric systems, as they fragment and weather, microplastics can migrate across trophic levels and even enter the human body via food, water, and air.
MPs are commonly classified as:
- Primary MPs: Manufactured at microscopic scale (cosmetic microbeads)
- Secondary MPs: Resulting from degradation of larger plastic waste
- Nanoplastics (NPs): Generally <1 µm; challenging to detect and quantify.
This discussion aims to provide a short overview of recent microplastic research and the chromatographic techniques utilized.
The Importance of Sample Preparation
Unlike conventional trace organics, MPs present unique challenges—heterogeneous size distributions, mixed polymer chemistries, strong matrix effects, and extreme sensitivity to contamination. Consequently, improper or insufficient sample prep can lead to inaccurate quantification, polymer misidentification, or false positives.
Given that MPs are airborne and omnipresent, preventing sample contamination is paramount:
- All containers and tools should be glass or metal; plastic labware (pipettes, tubes) can introduce background signals.
- Reagents must be filtered through 0.2 µm membranes to eliminate synthetic particles.
- Procedural blanks should be run with every batch to monitor contamination.
- Lab environments: Some labs use laminar flow hoods or cleanroom conditions, and analysts often wear cotton lab coats to avoid synthetic fiber shedding.
Thorough sample prep protocols enable accurate polymer identification, minimize matrix interferences, and improve reproducibility across complex environmental and biological samples.
The Core Chromatographic Techniques and Applications
Pyrolysis-gas chromatography–mass spectrometry (py-GC–MS) is a key technique used for polymer-specific quantification. The technique combines thermal decomposition (pyrolysis) of complex polymers with GC–MS, allowing for the identification of polymer types in solid or complex matrices without requiring complete dissolution or extraction.
Damia Barceló has published extensively on microplastics analysis and has recently published a method for the analysis of plastic polymers in samples collected from three Mediterranean beaches using py-GC–MS (1). The team analyzed 12 common polymers in environmental samples, achieving good linearity (R² > 0.97) and detection limits ranging from 0.1 µg (polyurethane [PU]) to 9.1 µg (polyethylene [PE]). Alongside Yolanda Pico, Barceló has also produced a review detailing recent instrumental advances and focusing on trends in the technique and application (2). More recently, he has published on the analysis and fate of MPs in wastewater, sludge, and landfills, highlighting the importance of environmentally friendly analytical methods for detecting MP pollution (3).
Microplastics have also been analyzed in the air using Py-GC–MS. A team of researchers quantified polystyrene (PS), polymethyl methacrylate (PMMA), polyethylene terephthalate (PET), polyvinyl chloride (PVC), PE, and polypropylene (PP) from urban PM₂.₅ samples collected in Shanghai (4). A study published in the Journal of Hazardous Materials has presented direct evidence of nanoplastic exposure in wild birds and emphasized their potential as bioindicators of airborne microplastic and nanoplastic pollution (5).
Liquid chromatography (LC) is less commonly used to detect microplastics. However, it is useful in the analysis of degradation products like oligomers and plastic additives, such as phthalates and bisphenols. Scientists from the University of Valencia in Valencia, Spain, recently developed a method for determining harmful dyes and additives released from polyester fibers (6). Thirteen compounds were extracted and quantified using solid-phase extraction (SPE) followed by high performance liquid chromatography coupled to high-resolution mass spectrometry (HPLC–HRMS/MS). Another study has demonstrated the benefits of liquid chromatography in the creation of an automatic flow-based system as a front end to LC for online dynamic leaching of microplastic materials (polyethylene of medium density and poly[vinyl chloride]) with incurred phthalates and bisphenol A (7).
The Impact on Human Health
Recent findings have shown the presence of MPs in human placenta, lungs, blood, and even brain tissue, raising new questions about particle uptake, transport, and long-term health effects.
Ragusa and colleagues published the first evidence of microplastics in human placenta in 2021, when 5–10 µm particles were identified using Raman microspectroscopy, suggesting maternal-fetal transfer potential (8). In 2022, a team from the Vrije Universiteit Amsterdam found PS, PE, and PET in human blood samples via Py-GC–MS (9).
More recently, a group led by Matthew Campen has detailed the bioaccumulation of MPs in decedent human brains using a combination of analytical techniques, including py-GC–MS, attenuated total reflectance–Fourier transform infrared spectroscopy (ATR–FT-IR), and electron microscopy with energy-dispersive spectroscopy (EM-EDS), to detect and characterize these particles (10). The study analyzed tissue samples from post-mortem subjects who passed away in 2016 and 2024 to examine the relationship of MPS concentrations over time. The findings revealed that MPs and NPs in these organs primarily consisted of PE, with lower but significant concentrations of other polymers. Notably, brain tissues recorded the highest proportions of PE (7–30 times greater) compared to the liver or kidney.
“I never would have imagined it was this high. I certainly don’t feel comfortable with this much plastic in my brain, and I don’t need to wait around 30 more years to find out what happens if the concentrations quadruple,” Campen remarked in a press release (11).
Outlook
Microplastics are now recognized as pervasive environmental contaminants with direct implications for human health. From water and air to human organs and tissues, their global reach underscores the urgency of robust analytical methods to track their presence, behavior, and biological interactions.
Do you work in microplastics analysis? Contribute to the conversation below.
References
(1) Santos, L. H. M. L. M.; Insa, S.; Arxe, M.; et al. Analysis of Microplastics in the Environment: Identification and Quantification of Trace Levels of Common Types of Plastic Polymers Using Pyrolysis-GC/MS. MethodsX 2023, 10, 102143. DOI: 10.1016/j.mex.2023.102143
(2) Picó, Y.; Barceló, D. Pyrolysis Gas Chromatography–Mass Spectrometry in Environmental Analysis: Focus on Organic Matter and Microplastics. TrAC 2020, 130, 115964. DOI: 10.1016/j.trac.2020.115964
(3) Mallek, M.; Barceló, D. Sustainable Analytical Approaches for Microplastics in Wastewater, Sludge, and Landfills: Challenges, Fate, and Green Chemistry Perspectives. Adv. Sample Prep 2025, 14, 100178. DOI: 10.1016/j.sampre.2025.100178
(4) Zhou, Y.; Fu, B.; Che, J.; Ye, X. Simultaneous Determination of Six Common Microplastics by a Domestic Py-GC/MS. atmosphere 2025, 16, 476. DOI: 10.3390/atmos16040476
(5) Wang, M.; Zhou, P.; DuBay, S.; et al. Assessing Microplastic and Nanoplastic Contamination in Bird Lungs: Evidence of Ecological Risks and Bioindicator Potential. J. Hazard Mater. 2025, 487, 137274. DOI: 10.1016/j.jhazmat.2025.137274
(6) Soursou, V.; De Falco, F.; Campo, J.; Pico, Y. A Multi-residue Method Based on Solid Phase Extraction Followed by HPLC-HRMS/MS Analysis for the Determination of Dyes and Additives Released from Polyester Fibres after Degradation. J. Chrom. A 2025, 1741, 465629. DOI: 10.1016/j.chroma.2024.465629
(7) Fikarova, K.; Cocovi-Solberg, D. J.; Rosende, M.; et al. A Flow-based Platform Hyphenated to On-line Liquid Chromatography for Automatic Leaching Tests of Chemical Additives from Microplastics into Seawater. J. Chrom. A 2019, 1602, 160–167. DOI: 10.1016/j.chroma.2019.06.041
(8) Ragusa, A.; Svelato, A.; Santacroce, C.; et al. Plasticenta: First Evidence of Microplastics in Human Placenta. Environ. Int. 2021, 146, 106274. DOI: 10.1016/j.envint.2020.106274
(9) Leslie, H. A.; Van Velzen, M. J. M.; Brandsma, S. H.; Discovery and quantification of plastic particle pollution in human blood. Environ. Int. 2022, 163, 107199. DOI: 10.1016/j.envint.2022.107199
(10) Nihart, A. J.; Garcia, M. A.; El Hayek, E.; et al. Bioaccumulation of Microplastics in Decedent Human Brains. Nat. Med. 2025, DOI: /10.1038/s41591-024-03453-1
(11) Haederle, M. UNM Researchers Find Alarmingly High Levels of Microplastics in Human Brains – and Concentrations are Growing Over Time [Press release] (Accessed 2025-02-03).
