For biological samples you first want to remove the organic components before pyrolysis, lest the subsequent mass spectrometry step produces false positives rather than an objective polymer analysis. In response to this paper a correspondence by Bianca Wilhelmus et al. replied with among other things the admission that the quantitative analysis of MNPs using Py-GC-MS is still in early stages of development. Especially since it seems harmful in mice, according to a 2025 study using starch-based plastics. With only Raman spectroscopes applicable for such fine analysis, it’s little wonder that Py-GC-MS is being applied to biological samples.