Identification of plastic additives: Py/TD-GC-HRMS method development and application on food containers

International audienceThe interest of studying organic plastic additives (OPAs) is growing since many of them are considered as toxic for human beings, marine organisms and have been found in the ecosystem. The impact and the extent of this pollution is not fully understood because of the lack of methods able to comprehensively analyze the wide diversity of OPAs. This study aims at offering a quick and efficient way to identify specific harmful plastic additives in polymer materials. For this purpose, a general method, for identifying 49 OPAs, has been successfully developed using pyrolyzer/thermal desorption-gas chromatography coupled to a high-resolution mass spectrometer (Py/TD-GC-HRMS). The retention indices were calculated for each compound and a high-resolution mass spectra database for plastic additives was implemented. This method was then applied to characterize the OPAs included in food containers that are frequently found in the environment. Four samples made of polypropylene (PP) and polylactic acid (PLA) coming from two distinct suppliers were then selected. A total of 10 additives, which were plasticizers (phthalates and adipates), antioxidants (bisphenol B) and phosphorous flames retardants, were found in these food packaging. Generally, higher peak signals were detected in the PP samples in comparison to PLA samples, except for tributyl phosphate and bisphenol B that were exclusively found in PLA samples. Moreover, the experimentations pointed out additives differences between suppliers, for products intended for the same use and made of the same polymer, for both PP and PLA samples highlighting the complexity of identifying and generalizing the additive content of plastic materials