Measuring and identifying micro- and nanoplastics (MNPs) in complex environmental and human samples is a daunting but important challenge to address. There are many laboratory methods being used across the field today, all with the aim of determining accurate amounts of plastics in humans and the environment to help assess potential health effects. A common analytical approach widely used in published MNP studies is pyrolysis-gas chromatography-mass spectrometry (Py-GC/MS). During the first part of this analytical process, pyrolysis is used to break down any plastic particles present into degradation products. These degradation products are subsequently separated based on their physical and chemical properties during gas chromatography and then finally identified using mass spectrometry. Working backwards by analyzing these degradation products, scientists can determine what type of plastic and how much of it was originally in the sample.
However, scientists have discovered that this Py-GC/MS approach can have significant pitfalls, in some cases limitations, and analyses using this method to measure MNPs needs expertise, particularly for complex samples, must be done carefully and with transparently to avoid wrong results. In a peer-reviewed article published in Microplastics and Nanoplastics on December 19, 2025, AURORA scientists Isabel Goßmann and Barbara Scholz-Böttcher together with colleagues from the Carl von Ossietzky University Oldenburg identified key challenges and shortcomings of applying Py-GC/MS to analyze polyvinyl chloride (PVC) plastic particles in complex samples.
One key issue the researchers illustrate is that the degradation products into which PVC breaks down during pyrolysis are not specific enough to PVC to reliably quantify PVC content in the samples. Naphtalene is one of the degradation products that has previously been proposed as an indicator for PVC. However, its widespread occurrence as pyrolysis degradation product for both natural (cotton), refractory materials like soot, and, although to lesser extent, synthetic (polyethylene, polyethylene terephthalate, polystyrene) polymers undermines its diagnostic value, the authors state. The same was shown for suggested alternative indicators like 1- and 2-methylnaphthalenes, dihydronaphthalene, and tetrahyronaphthalene.
The scientists call for caution when interpreting PVC signals identified using Py-GC/MS and other thermal methods. “Caution and thoughtful evaluation must be collectively addressed by the scientific community. Particulate MNPs undoubtedly represent one of the greatest analytical challenges. Thermal analysis already holds a significant and promising role in this field. Nevertheless, it is becoming increasingly clear that reliable results, especially for trace analysis, require a multi-method approach (e.g., complementary methods such as FTIR or Raman spectroscopy), to obtain a more comprehensive dataset and mitigate individual limitations,” the article concludes.
Scientists within the AURORA project are aware of the challenges involved with these analytical methods, and they are working to ensure robust, reliable, and transparent analysis of our samples. Overcoming such challenges is part of the scientific process. Critically evaluating and improving such scientific tools is expected, important, and does not invalidate the wider field of MNP research that has made significant advancements and contributions to protecting human and environmental health.
Reference
Goßmann, I., Wirth, C., and Scholz-Böttcher, B. M. (2025). “Reliable thermal mass quantification of PVC – an ongoing challenge.” Microplastics and Nanoplastics. DOI: 10.1186/s43591-025-00162-5
