The term oligomer refers to structurally diverse compounds coming from incomplete polymerisation or polymer degradation. Their ability to migrate into foodstuffs along with recent studies about their bioavailability and toxicity have risen concerns about the scarcity of standards necessary to perform analytical and toxicological studies. In this work, migration extracts of three starch-based biopolymers films destined to be in contact with fruits and vegetables were analysed according to European legislation 10/2011. UPLC-MS(QTOF) analysis allowed to identify a majority of oligoesters as non-intentionally added substances.

A stepwise synthesis approach was used to synthesise and isolate eleven cyclic and linear oligoester standards ranging from 2 to 8 monomers based on adipic acid, 1,4-Butanediol, isophtalic acid and propylene glycol monomers. Characterisation was performed by 1 H and 13 C NMR as well as high resolution mass spectrometry. An overall high purity of > 98 % was achieved as detected by UPLC-MS(Orbitrap). The standards were then used to unequivocally identify the oligoesters in the samples by comparing their UPLC-MS/MS spectra and to quantify or semi-quantify the migrant oligoesters in the samples. The results deemed safe only one out of the three biopolymer films according to the threshold of toxicological concern concept. The work herein described aims to contribute towards the oligomers knowledge gaps, opening the door for comprehensive risk and absorption, distribution, metabolism, excretion and toxicity (ADMET) assessments.