Occurrence of volatile contaminants in recycled poly(ethylene terephthalate) by HS-SPME-GCxGC-QTOF-MS combined with chemometrics for authenticity assessment of geographical recycling regions

A comparison was performed on various methods detecting the volatile contaminants (VCs) in recycled poly (ethylene terephthalate) (rPET) flakes, the results demonstrated that head-space solid phase micro-extraction combined with comprehensive two-dimensional gas chromatograph-tandem quadrupole-time-of-flight mass spectrometry (HS-SPME-GCxGC-QTOF-MS) was a sensitive, effective, accurate method, and successfully applied to analyze 57 rPET flakes collected from different recycling plants in China. A total of 212 VCs were tentatively identified, and the possible source were associated with plastic, food, and cosmetics. 45 VCs are classified as high-priority compounds with toxicity level IV or V and may pose a risk to human health. Combined chemometrics for further analysis revealed that significant differences among these three geographical recycling regions. 6, 7, and 6 volatile markers were chosen based on VIP values and S-plot among plant1 plant 2 and plant 3, respectively. The markers differed significantly between recycled rPET samples in three geographical recycling regions based on chemometrics analysis. The initial classification rate and cross-validation accuracy were 100% on the identified VCs. These significant differences demonstrate that a systematic study is needed to obtain a comprehensive data on the contamination of rPET for food contact applications in China.

Automated summary

A comparison was made on different methods for detecting volatile contaminants in recycled PET flakes, and HS-SPME-GCxGC-QTOF-MS was found to be a sensitive and accurate method for analyzing rPET flakes collected from recycling plants in China. 212 VCs were tentatively identified, with potential sources including plastic, food, and cosmetics. The study revealed significant differences in VCs among different recycling regions, and the chemometrics analysis selected volatile markers that differed significantly between these regions.