Session: Parallel session 1 - environmental analysis

Innovative approaches revealing environmental PET microplastics secrets

Polyethylene terephthalates are formed of terephthalic acid and ethylene glycol. Daily omnipresent, they constitute significant source of marine pollution. They degrade in the environment into micro- and nano-PET affecting environmental ecosystems. Nano-PETs have been detected in the water of PET bottles. No analytical method satisfies their quantification and identification on molecular level. Our new methodology allows the study of PET environmental alterations after weathering (UV, microorganisms, and salinity) or after waste treatment. It permits the study of modification’s degree between macro-PET and micro- or nano-PET affecting their toxicity. Many containers and bottles from different countries, brands and contents were analyzed. PETs were studied after accelerated UV-ageing and marine PET were also analyzed. Our methodology starts by solubilizing PET with hexafluoroisopropanol (HFIP) then transamidating it using N,N′-dimethyl-1,3-propanediamine (DMAPA). HFIP improves the extraction yield and allows a transamidation at room temperature. The products were neutralized, extracted and analyzed using MALDI FTICR MS 9.4 Tesla and Orbitrap LC-MS. For quantification, an internal standard was successfully synthesized. For better identifying polyols, we derivatized them by transesterification-benzoylation prior to their analysis. A successful depolymerization was marked by the presence of di-derivatized terephthalic acid. The analysis was sensitive on micro- and nano-sized plastics. For bottles, a specific signature was determined depending on their content, brand and manufacturing country. They were differentiated by their composition and the differences in intensities of the common peaks; dimers, oligomers, crosslinked and oxidized products. In most carbonated-containing liquid bottles, the presence of PETG made from cyclohexanedimethanol was detected. PET enchased products and additives were detected. The analysis of biodegradable copolyester PBAT will be shown.