Study of Products of the Alkaline Decomposition of Hydrolysis Lignin by Atmospheric Pressure Photoionization High-Resolution Mass Spectrometry

Abstract

A method of high resolution-mass spectrometry with acetone doped atmospheric pressure photoionization was used to study products of the alkaline solvolysis of hydrolysis lignin. It was found that the mass spectrum of the depolymerization products of hydrolysis lignin consists of about seven thousand peaks of oligomers, containing up to 10 aromatic units with an average molecular weight of 150 Da. Calculations of the elemental compositions of all detectable oligomers and their visualization on the van Krevelen coordinates allowed us to show that the studied sample differs from native (virgin released) lignin by the presence of fractions with high oxygen contents and highly unsaturated condensed structures, including polynuclear aromatic hydrocarbons. The structural units of lignin oligomers were characterized using an approach based on the collision induced dissociation of precursor ions in a broad m/z range.