Top–down lignomics analysis of the French oak lignin by atmospheric pressure photoionization and electrospray ionization quadrupole time‐of‐flight tandem mass spectrometry: Identification of a novel series of lignans

Abstract

We report herein the top–down lignomic analysis of virgin released lignin (VRL) extracted from the French oak wood using atmospheric pressure photoionization quadrupole orthogonal time‐of‐flight mass spectrometry (APPI‐QqTOF‐MS) (+ ion mode). Eight major protonated lignin oligomers were identified using the APPI‐QqTOF‐MS/MS of this complex VRL mixture without any kind of purification. This series of protonated oligomer ions were identified as neolignan cedrusin (1), five different aryltetralin lignans dimers (2–6), one lignan‐dehydroshikimic acid complex (7), and a lignan trimer (8). Similarly, electrospray ionization (ESI)‐QqTOF‐MS (+ ion mode) allowed us to identify three extra aryltetralin lignan derivatives (9–11). The Kendrick mass defect analysis was used for the simplification of this complex APPI‐QqTOF‐MS into a compositional map, which displayed clustering points of associated ions possessing analogous elemental composition. This series of novel protonated molecules were selected and subjected to low‐energy collision‐induced dissociation (CID)‐MS/MS analyses. The obtained gas‐phase fragmentation patterns helped to tentatively assign their most likely structures. Also, it was found that the use of different APPI and ESI ambient ionization techniques enhances the ionization of different types of lignin oligomers.

Mass spectrometry of polymers: A tutorial review

“…Kendrick analysis (Kendrick, 1963) and mass remainder analysis have become vital tools for mass spectrometric interpretation as they can convert spectra containing overlapping distributions as a result of multiple end groups, adduct ions, and variably charged species into a simple and easy‐to‐interpret 2D plot (Fouquet & Sato, 2017; Fouquet, 2019; Nagy et al, 2018). This type of data treatment is crucial for complex samples like crude oil (Marshall & Rodgers, 2008), mixtures of polymeric additives (Lacroix‐Andrivet et al, 2022), lignans (Mikhael et al, 2021), and other complex samples with superimposed isobaric and/or isomeric constituents (Fouquet, 2019). Examples of simplified data representation using Kendrick analysis on polymeric materials and mixtures are provided in Figure 28.…”

Utilising Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) to track the oxidation of lignin by an alkaliphilic laccase

“…More gentle ionisation techniques such as electrospray ionisation (ESI) and atmospheric photoionisation (APPI) and atmospheric pressure chemical ionisation being among the most used ionisation methods to reduce the fragmentation of lignin compounds during ionisation. [47][48][49][50][51] Whereas matrix-assisted laser desorption ionisation (MALDI) methods have also been used to study lignin to varying degrees of success with a recent study showing improved detection using graphite-assisted laser desorption ionisation of insoluble and soluble (Lignoboost & Kraft) lignin compounds. 52 A comprehensive overview of different MS methods and how they can be applied to lignin samples is outlined by Letourneau and Volmer.…”