Proficiency test on the determination of polyethylene and polybutylene terephthalate cyclic oligomers in a food simulant

Abstract

A proficiency test (PT) was organised by the European Union Reference Laboratory for Food Contact Materials (EURL-FCM) to assess the analytical performance of National Reference Laboratories (NRL) and Official Control Laboratories (OCL) in the determination of mass fractions of polyethylene terephthalate (PET) and polybutylene terephthalate (PBT) cyclic dimers and trimers in official food simulant. Homogeneity, stability and the assigned values of the test items were evaluated by EURL-FCM based on an in-house validated HPLC-UV method. The standard operating procedure was provided to participants as an alternative method to be used. Laboratory results were rated using z and ζ scores according to ISO 13528:2015. The PT assessment standard deviation (σpt) was set for the four oligomers investigated to 20 % of the assigned values. A total of 36 participants from 26 countries registered and reported results. They received two test items: - a food simulant fortified with a known mass fraction of the four oligomers, and - a fortified food simulant D1 after a migration experiment of a PET bottle. Most of the participating laboratories reported satisfactory results with z scores ranging from 70 to 85 %. This PT, organised for the first time at EU level, shows that most of the NRLs and OCLs are able to monitor the investigated measurands.JRC.F.5-Food and Feed Complianc