Combination of chemometrics and mass spectrometric methods for the data mining of molecular structure information of coal and biomass.

[Display omitted] • Spectral stitching improves the detection ability towards minor and trace species. • Comprehensive molecular information and transfer behavior of O and N atoms are revealed. • Similarity and difference of samples are visually exhibited in PCA and HCA plots. The combination of mass spectrometry (MS) data and chemometrics methods is conducive to obtaining more comprehensive molecular information and evaluating the transfer behavior of O and N atoms during the conversion of biomass and coal. In this work, 12 thermal dissolution (TD) extracts of coal/biomass samples and the catalytic hydrogenation products of TD extracts were analyzed by Orbitrap MS using spectral stitching and in-source collision-activated dissociation (ISCAD) methods. Spectral stitching improves the detection ability towards minor and trace species, enhancing the number of identified compounds by two times. Meanwhile, ISCAD provides more comprehensive molecular structure information, which can illustrate the transfer patterns of heteroatoms and deepen the understanding of the structural characteristics of aromatic rings during the conversion of biomass and coal. Two chemometrics methods, principal component analysis (PCA) and hierarchical cluster analysis (HCA), were introduced to dig out the detailed similarities and differences between O-containing and N-containing compounds in coal and biomass. HCA method not only recognized the category of O-containing and N-containing compounds in each sample, but also showed the removal behavior of O and N atoms in biomass and coal. Thus, the combination of MS methods and chemometrics method is expected to provide methodological support to elucidate the molecular structure and conversion pathways for complex coal and biomass. [ABSTRACT FROM AUTHOR]