Investigations into the characterization, degradation, and applications of biodegradable polymers by mass spectrometry

Abstract

Biodegradable polymers have been getting more and more attention because of their contribution to the plastic pollution environmental issues and to move towards a circular economy. Nevertheless, biodegradable materials still exhibit various disadvantages restraining a widespread use in the market. Therefore, additional research efforts are required to improve their performance. Mass spectrometry (MS) affords a relevant contribution to optimize biodegradable polymer synthesis, to confirm macromolecular structures, to examine along the time the progress of degradation processes and highlight advantages and drawbacks in the extensive applications. This review aims to provide an overview of the MS investigations carried out to support the synthesis of biodegradable polymers, with helpful information on undesirable products or polymerization mechanism, to understand deterioration pathways by the structure of degradation products and to follow drug release and pharmacokinetic. Additionally, it summarizes MS studies addressed on environmental and health issues related to the extensive use of plastic materials, that is, potential migration of additives or microplastics identification and quantification. The paper is focused on the most significant studies relating to synthetic and microbial biodegradable polymers published in the last 15 years, not including agro‐polymers such as proteins and polysaccharides.

Matrix-Assisted Laser Desorption and Electrospray Ionization Tandem Mass Spectrometry of Microbial and Synthetic Biodegradable Polymers

“…MALDI-TOF/TOF-MS/MS has been well used to study biodegradable polymer samples, such as polyesters and polyesteramides [19,38]. It disclosed structural information concerning the sequence of ester and amide bonds in synthetic polyesteramides [47,49,54] and the fragmentation mechanisms in biodegradable polyesters [48,52].…”

“…However, single-stage mass data are not always sufficient, for example, to verify definitely a polymer structure or samples in which isobaric or isomeric species are produced. In several instances, tandem MS (MS/MS) can be helpful confirming mass spectra interpretation and providing the supplementary information required [38][39][40][41][42][43]. In MS/MS, chosen precursor ions are induced to undertake chemical reactions, in most cases with unimolecular dissociations, changing their charge or mass.…”

“…MS/MS has been more and more employed to analyze synthetic polymers. In fact, it can provide significant information on end groups or inchain functionalization, distinguish isobaric and isomeric chains, differentiate linear and cyclic species, and reveal macromolecular connectivity, sequence distribution, and complex architectures [14,38,39,41,[44][45][46][47]. For assertive structure assignments, preliminary studies on the fragmentation pathways are the first step to understanding MS/MS spectra.…”

“…In fact, the comprehension of the preferred fragmentation processes represents a sort of guideline on how to establish the structure of diagnostic product ions detected in tandem with MS spectra and then go back to the macromolecular structure [40]. The collision-induced dissociation (CID) approach is the most adopted fragmentation tool for the structural characterization of gas-phase ions [38,39,42,[44][45][46][47][48][49][50].…”

“…More recently, several studies have been focused on DDS and pharmacokinetics by MS/MS, thanks to the technological progress and combining ESI with separation techniques. Overall, MS has been more extensively employed in the analyses of biodegradable polymers [14][15][16]19,21,23,25,28,[31][32][33][34][35][36][37]44,128] than tandem MS [38][39][40][41][42][43]45], even if MS/MS is highly informative. This should be reasonably due to the time-consuming step related to the data processing and interpretation in MS/MS [14,15,19,28,39,42], even though tandem MS analysis has provided valuable information on biodegradable polymer architectures, end-group functionalities, bond connectivity, copolymer sequences, etc.…”