Optimization of pyrolysis-gas chromatography/mass spectroscopy parameters in order to obtain nanoplastics calibration curves

The issue of plastic pollution is one of the challenges of the coming years. When it comes to agriculture, this material is widely used, although its degradation leads to formation of micro- and nanoplastics, whose impact is being studied within the Minagris project. In particular, the identification and quantification of nanoplastics in soil can be challenging due to their size, which is below the special resolution of several techniques typically used for the characterization, as Raman or μ-FTIR analysis. Furthermore, the presence of organic matter or biological agents makes these techniques unsuitable for this purpose. Pyrolysis-gas chromatography/mass spectroscopy enables to investigate nanosized plastic samples with low limit of detection (LOD) and limit of quantification (LOQ). In this work, some of the main types of plastic used in farming have been tested at the nanoscale; with optimized parameters of py-GC/MS, calibration curves of these polymers have been obtained, in order to test out the likelihood of analysing them not only qualitatively, but also quantitively. Strong linear correlation has been found between the peak areas of the markers of each polymer and its quantity under analysis, an outcome that may be useful for real nanoplastic samples.