Quantitation of polystyrene by pyrolysis-GC-MS: The impact of polymer standards on micro and nanoplastic analysis

The analytical method for detecting and quantifying micro and nanoplastics (MNPs) using Pyrolysis-Gas Chromatography-Mass Spectrometry (Py-GC-MS) is evolving and continuously refined. The requirement for accurate analytical methods faces challenges during method validation due to the scarcity of relevant reference materials. Additionally, the wide array of polymer types and their diverse characteristics further complicate this validation process. This study evaluated the impact of using diverse polystyrene (PS) standards with different molecular weights, polydispersity indexes, tacticity, endcapping, and chain branching, on quantifying the mass concentration of PS in various products. The results for the PS-based products showed inconsistencies across different standards, indicating that the measurements for a single product varied substantially when different polystyrene (PS) standards were applied. The influence of sample quantity on pyrolysis revealed differences in the ratios of pyrolysis products among various PS standards and different sample amounts. This research emphasizes the complexities involved in the precise quantification of polymers using Py-GC-MS. It provides valuable insights crucial for quantitative MNP analysis, highlighting the need for refined calibration strategies and standardised reference materials to improve the reliability of the MNP analysis method.