The characterization and influence factors of semi-volatile compounds from mechanically recycled polyethylene terephthalate (rPET) by combining GC?GC-TOFMS and chemometrics

A non-targeted method was developed for screening the semi-volatile compounds of different mechanically recycled PET intended for food contact materials. The data was further analyzed by multiple chemometrics methods to obtain the difference level, and the potential influence factors were investigated. The results showed that total dissolution with comprehensive two-dimensional gas chromatography coupled with time-of-flight mass spectrometry was more effective than other reported methods. Based on the difference level, 97 compounds were characterized into 4 levels. 1-Methyl-2-pyrrolidinone originating from organic solvent was recognized as level IV and could be determined as the primary difference indicator. The contaminant is mainly attributed to the residuum derived from non-food consumer products. The specific types of contaminants and process parameters of the recycling, such as moisture content, properties of rPET, and temperature, were the potential key factors affecting the presence of semi-volatile compounds of mechanically recycled rPET.

Automated summary

A non-targeted method for screening the semi-volatile compounds of mechanically recycled PET for food contact materials was developed, and multiple chemometrics methods were used to analyze the data and investigate the potential influence factors. The results showed that total dissolution with comprehensive two-dimensional gas chromatography coupled with time-of-flight mass spectrometry was the most effective method. 97 compounds were classified into 4 levels based on their difference levels, with 1-Methyl-2-pyrrolidinone recognized as the primary difference indicator. The contaminant was mainly derived from residuum of non-food consumer products. The specific types of contaminants and process parameters of the recycling, such as moisture content, properties of rPET, and temperature, were found to be potential key factors affecting the presence of semi-volatile compounds in mechanically recycled rPET.