Scientists around the world have been searching food, water, and other environmental media for microplastics and for per- and polyfluoroalkyl substances (PFAS). But microfluoroplastics (MFPs), the intersection between these two fields, have received much less attention.
Now researchers have developed new procedures to extract and measure microplastic particles from six different fluoropolymers (Environ. Sci. Technol. 2026, DOI: 10.1021/acs.est.6c04873). The research team detected all six types—four for the first time—in archived spectra of dust, suspended particulate, and sediment samples. The MFPs overall comprised roughly 2–8% of the total microplastics reflected in those spectra.
Chu Peng at Nankai University and his colleagues realized that scant attention had been paid to MFPs when they set out to measure them and found no reference spectra beyond that of polytetrafluoroethylene (PTFE). Subsequently, they began collaborating with the technical department of Agilent China to prepare a library of reference spectra for six fluoropolymers: PTFE, polyvinylidene fluoride (PVDF), PVDF-hexafluoropropylene copolymer (PVDF-HFP), polytrifluorochloroethylene (PCTFE), ethylene chlorotrifluoroethylene (ECTFE), and fluorinated ethylene propylene (FEP).
To create the reference spectra, the researchers opted for Agilent’s laser direct infrared (LDIR) spectroscopy technique, an emerging tool in microplastics research. LDIR measures the same infrared absorption of polymers as traditional Fourier transform infrared (FTIR) spectroscopy does, except it’s faster, says Peng. That’s because LDIR scans a smaller range of wavelengths (900–1800 cm-1) than FTIR, which scans the full range of 400–4,000 cm-1. The C–F bonds characteristic of fluoropolymers fall within that narrower wavelength window, he says, making the LDIR technique suitable for MFPs.
Peng and his colleagues prepared each of the six types of MFPs in six granule sizes and two fiber lengths. They also prepared a set of chemically aged MFPs to mimic the effects of weathering in the environment.
Then they turned to sample preparation. For detection, microplastics need to be exposed fairly well on a surface so that they can be hit by the light from a spectrometer. Typically, researchers digest food, dust, or sediment samples to remove organic matter that could aggregate with microplastics and interfere with the detection, but the digestion procedure must also be gentle to avoid destroying the microplastics themselves, Peng explains.
But since MFPs are much tougher, the researchers developed a harsher procedure by subjecting MFPs to a strong acid, then a strong base, and finally an organic solvent—revealing some 67–100% more MFPs. “They basically decreased the background signal . . . so that was a good step,” says Rainer Lohmann, an environmental scientist of the University of Rhode Island who was not involved in the study. The same sample would have to undergo both the conventional gentle digestion and the harsh one to measure all the microplastics, Lohmann says, but the new protocol is still useful. “You can get more information out of the sample that you have collected.”
The LDIR instrument is commercially available, so these reported methods to measure MFPs should be “easily adaptable” by different research groups, says Rolf Halden, an environmental health engineer of Arizona State University who was not involved in the study. Halden also appreciates that Peng and his colleagues have prepared and measured MFPs that were aged, as they found clear spectral differences between new and weathered MFPs. Meanwhile, differences in particle sizes or shapes did not affect the spectra.
The researchers applied their sample preparation method and used their reference library to measure the PTFE MFPs produced by cooking in nonstick pans. Frying eggs produced 3,890–6,760 PTFE microplastic particles in food, while boiling noodles produced 2120-4960; cooking in older, scratched pans yielded more MFPs than cooking in new pans. For comparison, microwaving water in a polypropylene container for 3 min released millions of microplastic particles in a 2023 study.
When the researchers analyzed an archive of microplastics spectra against the new reference spectra for MFPs, they found all six fluoropolymer types, with PTFE being the most prevalent, followed by the specialty fluoropolymer ECTFE.
Specialty fluoropolymers are prized in high-tech industries such as aviation, semiconductor manufacturing, and pharmaceutical manufacturing. Polyvinylidene fluoride (PVDF), for example, can be found protecting wires and cables like the ones shown, while others could be lining the interior of vessels, or made into the piping, O-rings, and gaskets in those demanding settings. Credit:
Shutterstock
At this stage, both Halden and Lohmann believe it is difficult to tell what the researchers’ measurements of MFPs mean for environmental and human health, particularly because the toxicological piece of the puzzle is missing.
For PFAS researchers who often cannot account for all the organic fluorine in their dust or sediment samples, MFPs could help explain the missing fluorine, Lohmann says.
Because fluoropolymers are used heavily in electronics, Peng and his colleagues plan to sample areas around plants where electronic waste is dismantled and analyze them for MFPs. They also plan to look for any ingested MFPs in human stool samples.
