Développement d'une méthode de quantification des microplastiques par Pyr-GC-MS pour l'analyse de sédiments de la Seine

Pyrolysis-GC-MS is increasingly used to quantify microplastics and can be applied to the analysis of environmental samples, although methodological developments are still required. This method gives access to a concentration of MP in polymer mass and can thus be used as a complement to micro-IRTF and Raman spectroscopy methods which provide information on the number and shape of particles. In the literature, several indicator compounds are proposed in Pyr-GC-MS as markers of plastic polymers. This report proposes a review and selection of these indicator compounds based on potential interactions with substances present in environmental matrices for the most common polymers: PE, PP, PS, PET and PVC. The elements that supported the choice of a protocol for sediments are detailed and the protocol is applied to a sediment sample from the Seine river. After treatment by density separation followed by digestion of the organic matter, an organic and inorganic matrix residue was observed in the sample. Matrix effects due to the residual mineral fraction were demonstrated for the indicator compounds selected for MP quantification. Demonstration of these matrix effects supports the development and validation of an internal calibration quantification in sediments.