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Matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry analysis for characterization of lignin oligomers using cationization techniques and 2,5‐dihydroxyacetophenone (DHAP) matrix
Author(s) -
Bowman Amber S.,
Asare Shardrack O.,
Lynn Bert C.
Publication year - 2019
Publication title -
rapid communications in mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.528
H-Index - 136
eISSN - 1097-0231
pISSN - 0951-4198
DOI - 10.1002/rcm.8406
Subject(s) - chemistry , lignin , dhap , mass spectrometry , oligomer , matrix (chemical analysis) , desorption , analytical chemistry (journal) , organic chemistry , chromatography , adsorption , enzyme
Rationale Effective analytical techniques are needed to characterize lignin products for the generation of renewable carbon sources. Application of matrix‐assisted laser desorption/ionization (MALDI) in lignin analysis is limited because of poor ionization efficiency. In this study, we explored the potential of cationization along with a 2,5‐dihydroxyacetophenone (DHAP) matrix to characterize model lignin oligomers. Methods Synthesized lignin oligomers were analyzed using the developed MALDI method. Two matrix systems, DHAP and α‐cyano‐4‐hydroxycinnamic acid (CHCA), and three cations (lithium, sodium, silver) were evaluated using a Bruker UltraFlextreme time‐of‐flight mass spectrometer. Instrumental parameters, cation concentration, matrix, sample concentrations, and sample spotting protocols were optimized for improved results. Results The DHAP/Li + combination was effective for dimer analysis as lithium adducts. Spectra from DHP and ferric chloride oligomers showed improved signal intensities up to decamers ( m/z 1823 for the FeCl 3 system) and provided insights into differences in the oligomerization mechanism. Spectra from a mixed DHP oligomer system containing H, G, and S units showed contributions from all monolignols within an oligomer level (e.g. tetramer level). Conclusions The DHAP/Li + method presented in this work shows promise to be an effective analytical tool for lignin analysis by MALDI and may provide a tool to assess lignin break‐down efforts facilitating renewable products from lignin.