Do we really have enough plastic in our brains to make a spoon?

So many plastic particles are crossing our blood-brain barrier that some brains may hold enough plastic to make a disposable spoon. That is the shocking conclusion reached by Matthew J. Campen, Regents’ Professor of pharmaceutical sciences at the University of New Mexico, based on a 2025 study he led. Several other studies have also identified large numbers of plastic particles in human organs and placentas.

The findings have potentially huge implications for human health. But not everyone accepts them.

Many analytical chemists say that quality controls, which are necessary to obtain reliable results associated with microplastics, may have been overlooked. For example, fat in brain tissue can be mistaken for polyethylene, and some say this misidentification may have happened in the Campen study.

Questions about the findings of such studies have pushed the nascent field of plastics analysis into a state of uncertainty. Analytical chemists attending the Analytica instrumentation exhibition and conference in Munich last month said they are motivated to develop robust methodologies that will help the field advance beyond its current level of understanding. But analysis of microplastics is so fiendishly complicated—especially at the nanoscale—that ensuring studies are robust and replicable is a huge challenge.

Studying microplastics using advanced analytical techniques

Researchers talk about two kinds of tiny plastic particles: microplastics and nanoplastics. Microplastics are defined as particles below 5 mm in size, and nanoplastics as particles below 1 μm. Spectroscopy and microscopy are widely used, independently or in combination, to analyze these particles, which are collectively known as MNPs.

Pyrolysis–gas chromatography–mass spectrometry (Py-GC/MS), a thermo-analytical technique, is broadly accepted as a way to determine the mass and polymer type of MNPs. In the method, an MNP sample is heated so it degrades under high temperature in the absence of oxygen. The gaseous degradation products are then fed into a GC/MS instrument. Sample preparation is key because biological material and other contaminants can falsely indicate the presence of polymers like polyethylene and polyvinyl chloride.

Scientists also use other spectroscopic methods to determine MNP polymer type. Detection and characterization of microplastics down to about 10 μm can be achieved using Fourier transform infrared (FT-IR) spectroscopy, a rapid, nondestructive technique that identifies organic and inorganic materials by measuring how they absorb infrared light. Characterization of particles well into the nanoscale may also be achieved using Raman spectroscopy—or versions of it—which involves illuminating a substance with a laser and analyzing the light that is scattered.

Meanwhile, microscopy is important for detecting and characterizing MNPs above about 1 μm. Unlike spectroscopic methods, microscopy allows scientists to view particles directly. In addition to shape and size, it enables analysis of particle color and surface texture. Particle counting is also possible.

Combining microscopy with spectroscopy in various ways can yield additional information about particles, including nanoparticles. An example is Raman microscopy, which can yield reliable identification, quantification, and characterization of plastic particles down to 500 nm.

Contamination is possible at every step

Studying the presence of microplastics in drinking water is about as straightforward as MNP analysis can get, but even here, it is easy to make errors, Nicole Zumbülte, senior scientist at the German Technical and Scientific Association for Gas and Water (DVGW) Water Technology Center (TZW), told delegates at Analytica. “You can have real cross-contamination in the lab through clothes, dust, and also the instruments,” she said.

At each step, researchers need to test what are known as blank samples to measure how much background contamination is present. “You have to think about what materials you can use” because it could result in a false positive, she said. “This can happen during the sampling, the sample preparation, and also later on in the analysis.”

Zumbülte recalled a past study where she and colleagues were analyzing samples from drinking-water companies and finding “tons of polyethylene” in the blank value. “We checked everything. We did it several times and repeated and repeated with reference materials. And it came out that when we have too much water on the [lab] gloves, then we have more polyethylene. We avoid gloves nowadays,” she said. But the room for error doesn’t end there. “We have a really strict hand wash protocol,” she said.

And yet Zumbülte’s finding that lab gloves contaminate MNP samples isn’t universally known in the field. Like Zumbülte, Madeline E. Clough, who recently graduated with a PhD from the University of Michigan, went through multiple repeats of analytical steps, only to find that lab gloves were causing false positive readings for plastic particles. Clough and colleagues published their findings last month in the journal Analytical Methods.

“Our team found that common lab gloves can shed particles that look just like microplastics, leading to inflated counts in environmental samples,” Clough states on her LinkedIn page.

Widespread lack of understanding about the potential of lab gloves to contaminate samples raises questions about the accuracy of years of microplastics studies.

But even as presentations and publications raise awareness about contamination from gloves, the field has yet to agree on how to handle the problem. There is “division” among scientists about the actions they should take to avoid contamination from gloves, Clough and her colleagues warn in their study.

While contamination can occur at every analytical step, the basic methodology for microplastics analysis is broadly accepted. “For microplastic analysis, we can apply either particle-based methods such as FT-IR and Raman spectroscopy, or mass-based methods, such as pyrolysis-GC/MS,” said Natalia P. Ivleva, head of the Raman and scanning electron microscopy group and chair of analytical chemistry and water chemistry at the Technical University of Munich.

“For microplastic from 10 or 20 μm, we already have well-established analytical methods,” she told C&EN after presenting at Analytica.

Strict protocols for sample preparation are, though, key to getting accurate results. Organic matter and metals can distort results if they are not removed from samples. For example, ferrous minerals in environmental samples can cause signal suppression when Py-GC/MS is applied, said Georg Dierkes, a scientist with Germany’s Federal Institute of Hydrology, during his talk at the conference in Munich.

“An extensive type of preparation is mandatory if you want to quantify microplastic in complex environmental samples,” he said. “The quantification of synthetic polymers in complex environmental samples is a highly challenging task.”

Nanoplastics analysis is even more challenging

“For smaller plastic particles, we still have methodological challenges,” Ivleva said. At the nanoscale, automation and appropriate subsampling strategies are indispensable because if an insufficient number of particles is measured, the extrapolation needed can yield erroneous results.

“For nanoplastic, since particles are so small and mass is so low, we definitely need much better sample preparation, including preconcentration and enrichment. We need size examination, and only then we can do chemical analysis,” Ivleva said.

Ivleva added that an underlying problem is that nonexperts are often studying MNPs. “Microplastics and nanoplastics have become such a broad and interdisciplinary topic that their analysis is sometimes carried out by people with very little knowledge of analytical chemistry, and they ignore the basic principles of how to make the sampling, preparation, and measurement,” she said.

“Some people try to use unreliable results to draw correlations between particles which they have found and some diseases,” Ivleva said. “In reality, this can only be done if the analytical data is trustworthy.”

A clear pathway for MNP analysis is emerging

From the outside, the nascent field of MNP analysis appears to be in chaos. Even some basic components of MNP analysis, such as making blank samples to determine background MNP levels, are not yet agreed upon. “What is the perfect blank? This is, I think, the most important question,” said Sebastian Primpke, a specialist in the study of microplastics using FT-IR and Raman spectroscopy at the Alfred Wegener Institute, Helmholtz Center for Polar and Marine Research, in conversation with C&EN after presenting his research at Analytica.

Still, analytical chemists are optimistic that the field is headed in the right direction. A clear set of protocols for studying MNPs is emerging and awareness of false positives is greater, so the analytical uncertainty in the sector is decreasing, Stephan Wagner, professor of environmental analysis at Fresenius Hochschule University of Applied Sciences, said after chairing Analytica’s symposium session on plastics analysis. “Imagine 5 years ago it was even more chaotic,” he said.

Momentum to develop standard methods is growing, especially in Europe, where the European Commission (EC) is set to introduce legislation in 2029 (PDF) that will require drinking-water providers to determine the risk posed by MNPs in water intended for human consumption. The pending law is driving water companies to commission research into robust methods for microplastics analysis.

In anticipation of the regulation, the Joint Research Centre, an EC agency, is developing monitoring methodologies and certified reference materials to ensure that microplastics monitoring is enforceable.

The International Organization for Standardization (ISO), a nongovernmental standard-setting group, is building a global technical framework for microplastics analysis, featuring definitions, analytical options, and more, primarily for regulators. The ISO’s approach is broader than the Joint Research Centre’s and includes methodologies spanning water, soil, textiles, and air. The ISO has also begun working on standards for analyzing nanoplastics.

Meanwhile, understanding how to avoid errors in MNP analysis is building. “I see now that people try to do it more properly and understand all steps, from representative sampling through optimized sample preparation to instrumental analytics,” Ivleva said.

Instrumentation is enabling advances in MNP analysis

In a further boost for the discipline, instrument companies are developing analytical tools that are better at counting particles and determining what types of plastics are present. “Analytical instrument methods are getting mature,” Wagner said. “The instruments are available, the manufacturers are aware, and they’re optimizing these instruments for these tasks with particle detection. And the software’s getting better.”

Just a 5 min walk from the focus and calm of the Analytica conference and its poster display zone were the noisy, thronging exhibition halls, where myriad companies showed off new instruments that could advance the analysis of MNPs.

Among them, PerkinElmer unveiled its Spotlight Aurora-I FT-IR microscope, which can identify unknown samples and contaminants with real-time spectral matching. The instrument will enable scientists to quickly “get a clear and precise” analysis of microplastics, said chief technology officer Dominic Gostick.

Another Analytica exhibitor, the instrument maker Metrohm, displayed a portable Raman spectrometer that it claimed is highly suited to analyzing microplastics in the field. “You put the sample in the top, and it takes just a few seconds to analyze,” said Metrohm sales engineer Mikaela Farzian.

Scientists at the conference attested to the power of having more-advanced instrumentation. “For example, by using optical photothermal infrared spectroscopy, we can analyze particles down to 1 micron [1 μm] or even 500 or 300 nm,” Ivleva said of the size of plastic particle her lab can detect. Artificial intelligence may help with the analysis, but before it can be used, good results must be created, she said.

Ivleva has her eye on a stimulated Raman spectroscope featuring two lasers that can improve the sensitivity of Raman analysis by several orders of magnitude. Such technology will help scientists get closer to understanding the fate of MNPs in the human body and the environment.

As better instruments, standardized methods, and new ways of avoiding errors are adopted, scientists researching MNPs say they will be in a position to provide more clarity about the threat posed by plastic pollution.

And as for Campen’s 2025 study, although some analytical chemists do not accept all the findings, it has not been disproved. Campen’s take is that more research needs to be done so society can understand what is going on—and the sooner the better. “At some point, dose makes the poison, and the concentrations in the environment and our body are rising over time,” he tells C&EN in an email. “So, it is important to better study this now, as it may take 50 years to reduce the environmental burden.”

Alex Scott is a C&EN business reporter covering all chemistry-related issues in Europe.

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