Abstract
The oligomeric fraction of polyethylene terephthalate (PET) has been studied as it has the potential to migrate to foods and beverages packaged in virgin and recovered PET plastics. We have applied positive ion atmospheric-pressure chemical ionisation (APCI) to extracts of food-grade PET resin and beverage bottles. A reversed-phase HPLC system was connected directly to a VG Platform mass spectrometer. An acetonitrile-water-acetic acid gradient elution was performed. Low APCI probe temperatures (as appropriate for a polyethylene glycol calibrant) produced no significant ions from a PET cyclic trimer standard. A high probe temperature of 500–600°C gave a strong protonated molecular ion. Characteristic spectra of the cyclic oligomers from the trimer to the heptamer were obtained. A second homologous series of substances 44 mass units higher than each PET oligomers eluted prior to each PET oligomer. The mass spectra indicated these to be oligomers with one monoethylene glycol unit replaced by a diethylene glycol unit. To our knowledge this is the first time that cyclic oligomers above the tetramer have been confirmed by LC-MS. The technique was considerably more sensitive than published thermospray methods and gave food spectra with sub-microgram quantities injected. This work demonstrates the advantages of APCI over thermospray as an MS technique for substances of this type.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
