Abstract: Commercially available straw samples were collected for compositional analysis by Fourier transform infrared (FT-IR) spectroscopy, and the non-targeted analysis of volatile compounds in the straw samples was performed by gas chromatography-mass spectrometry (GC-MS). The compounds were identified using retention index, the National Institute of Standards and Technology (NIST) mass spectral library and mass spectrometry-data-independent acquisition (MS-DIAL) deconvolution, and relevant databases were used for traceability analysis and to identify compounds of safety concern. The results showed that the samples were all found to comprise PLA alone or mixed with poly(butyleneadipate-co-terephthalate) (PBAT) and poly(butylene succinate) (PBS) in different proportions. Totally 41 volatile substances were detected by GC-MS, and 173 volatile substances by headspace GC-MS (HS-GC-MS), mainly plastic additives and pesticides and detergents that may originate from raw materials, and the safety of some substances should be of concern. The results of GC-MS and HS-GC-MS were complementary to each other, which is beneficial for more accurate analysis of volatile substances. This study provides a basis for the analysis and safety risk assessment of volatile substances in commercially available PLA straws.

Key words: polylactic acid straws; gas chromatography-mass spectrometry; volatile compounds; Fourier transform infrared spectroscopy