The Fractionation and Characterization of Nanoplastics in Environmental and Food Science

A recent study published in the journal Analytical Chemistry demonstrated a novel analytical technique for detecting nanoplastics in complex biological samples, coupling asymmetrical flow field-flow fractionation multidetection (AF4-MD) with Raman microspectroscopy to analyze polystyrene nanoplastic beads (100–500 nm) directly in unprocessed milk, without the laborious sample pretreatment typically required by existing methods.¹ This study represented, according to the authors, the first application of AF4-MD-RM to a real, unprocessed matrix (previous work was limited to aqueous environments).¹

The findings from this study will be presented at the SciX 2026 Conference, which will take place from October 4–9, 2026, in Sparks, Nevada at the Nugget Casino Resort.²

What are the important details of the talk attendees should know?

The group leader, Natalia P. Ivleva of Technical University of Munich, will deliver her team’s talk as part of a technical session titled “Emerging Raman.” Ivleva’s talk, which is titled “Raman Microspectroscopy Online Coupled with Field-Flow Fractionation for Analysis of Nanoplastic Particles: From Water to Milk Matrices,” will take place on Monday October 5^th at 11:10 am local time in the Cascade 4 conference room.³

What will Ivleva’s talk cover?

Ivleva will present her team’s new online analytical method that combines field-flow fractionation (FFF) with Raman microspectroscopy to separate and chemically identify nanoplastics, which are particles smaller than 1 um, in complex matrices such as milk, without requiring sample pretreatment.³ This approach addresses a longstanding gap in nanoplastics analysis, which is the ability to distinguish plastic particles from non-plastic particles of similar size in a single, size-resolved workflow.^1,3

Why are nanoplastics a concern in environmental and food science?

Nanoplastics are increasingly recognized as a concern in environmental and food science, as well as in human toxicology, because their small size allows them to penetrate cell membranes, raising the possibility of eco-toxicological harm.^1,3 Until now, analytical chemists have lacked validated, routine methods capable of both sizing these particles and confirming their chemical identity in the same measurement.^1,3

How can field-flow fractionation (FFF) platforms with multidetector systems address current limitation?

FFF platforms equipped with multidetector systems can already separate and characterize particles by size.³ However, size data alone cannot confirm whether a given particle is plastic or a naturally occurring material such as silica, titanium dioxide, or iron oxide.³ Ivleva will discuss in her talk how Raman microspectroscopy fills that gap by generating chemical fingerprint spectra. Because Raman microspectroscopy is insensitive to water, it can be applied directly to wet samples and suspensions rather than requiring drying or extraction steps that risk altering the sample.³

What was the technical challenge that the researchers faced in their study?

The main challenge the researchers encountered was signal strength. Raman scattering from individual particles in dilute suspensions is typically too weak to detect reliably as particles flow past a detector.³ Resolving this issue required the researchers to construct a flow cell that used optical tweezers to hold particles in place long enough to collect a usable Raman signal while the particles remain in the flowing stream, enabling true online coupling rather than offline, fraction-by-fraction analysis.^1,3

How did the team validate their system?

In her upcoming talk, Ivleva will review how her team tested the coupled system to ensure it operated as intended. She will describe how her team validated the coupled system using suspensions of both plastic particles (polystyrene, polyethylene, and PMMA) and non-plastic particles (silica, titanium dioxide, and iron oxides) ranging from 100 nanometers to 5 um, in both mono- and polydisperse mixtures.³

Two FFF formats tested this system. The first was asymmetric flow FFF (AF4), suited to size-based separation of particles from roughly 1 nm to 1 um, and centrifugal FFF (CF3), which separates by both size and density across a broader range of roughly 10 nm to 50 um.³ In both configurations, the multi-angle light scattering (MALS) detector supplied physical sizing data while Raman microspectroscopy supplied chemical identification, effectively producing two complementary data sets from a single run.³

Then, Ivleva and her team applied the method to a real-world food matrix, spiking milk with polystyrene beads ranging from 100 to 500 nanometers.^1,3 The system separated and identified the plastic particles alongside native milk components without any sample pretreatment.^1,3 To confirm their findings, the team cross-checked collected fractions using two independent offline techniques, scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDX) and nanoparticle tracking analysis (NTA), both of which corroborated the FFF-RM results.³

Ivleva’s talk at SciX will go into detail about the methodology used in the study, ultimately demonstrating that a single-platform workflow for characterizing nanoplastics in food and environmental testing laboratories is achievable.

References

1. Giordani, S.; Huber, M. J.; Jungling, I. S.; Zattoni, A.; Roda, B.; Reschiglian, P.; Marassi, V.; Ivleva, N. P. Online Coupling of Field-Flow Fractionation with Raman Microspectroscopy Enables the Advanced Study of Nanoplastics Directly in Food. Anal. Chem. 2026, 98 (1), 488–496. DOI: 10.1021/acs.analchem.5c05137
2. Wetzel, W.; Spectroscopy Staff. Previewing the Upcoming 2026 SciX Conference. Spectroscopy Online, 2026. https://www.spectroscopyonline.com/view/previewing-the-upcoming-2026-scix-conference (accessed September 2, 2026).
3. Ivleva, N. P. Raman Microspectroscopy Online Coupled with Field-Flow Fractionation for Analysis of Nanoplastic Particles: From Water to Milk Matrices. Presented at the SciX 2026 Conference, Sparks, Nevada, October 5, 2026. Available at: https://www.scixconference.org/onlineprogram