Study Of Biomarkers Based On Mass Spectrometry Imaging

Biomarkers play an important role in geochemistry and oil and gas exploration.The study of biomarker parent can promote the understanding of geological evolution and hydrocarbon forming environment.At present,researches on biomarkers mainly focus on geological bodies,but fewer in-depth study on the biomarker parent.Here,a kind of main biomarker parent,wood extractives,was taken as the study object,via the comprehensive characterization of molecular composition and the accurate trace for biomarkers,so that promote the understanding of the biomarker matrix.Gas chromatography-mass spectrometry(GC-MS)is the mainstream method for the analysis plant compositions,it is incapable of achieving the above two objectives due to its limit for the boiling point of analytes and the resolution of MS.Therefore,more advanced analytical methods should be developed.At present,an integrated analytical method for the comprehensive characterization of the molecular composition of woody extracts is in lack.The successful application of ultra-high resolution mass spectrometry in "petroleomics" proves its strengths in characterizing complex organic systems at the molecular level.In this paper,the method of characterizing molecular compositions in extractives of xylem based on ultra-high resolution mass spectrometry was established.The compatibility and selectivity of extraction ability for different solvents were investigated,an ultra-high resolution mass spectrometry based method was established for the determination of extractives,multidimensional statistical methods was used to characterize the compositions of extractives.The results expanded the library of extractives greatly,and realize the chemodiversity analysis of extractives from various of solvents.The biomarker parent undergoes various migrations and transformations in wood,such as transformation from sapwood to heartwood,resin migration,etc.,in-depth excavation of their distribution in the xylem is helpful for accurate tracing.In order to fill in the spatial distribution information of biomarkers based on the molecular composition information,matrix-assisted laser desorption/ionization mass spectrometry(MALDI MSI)method was further developed,the accurate localization of biomarkers on the cross section of xylem was realized.an effective matrix-assisted ionization method was determined by investigating organic and inorganic matrixes;the difficulty of sample preparation was overcome by exploring slicing and matrix coating method;the recognition of molecular distribution at the spatial resolution of 70 ?m can be realized by the established MSI method,which satisfying the identification of biomarkers in xylem;the efficiency and qualitative accuracy was ensured by the developed multichannel data analysis method.Finally,the in-situ detection of biomarkers was innovatively realized,and the transformation of biomarkers from sapwood to heartwood was observed,and the rule of migration and accumulation of biomarkers was preliminarily explored.At the same time,the heterogenous distribution of different types of resin were observed,and the source of resin was traced by combining molecular structure identification and distribution characteristics.In this paper,an ultra-high resolution mass spectrometry-based method was developed to characterize the molecular composition of wood,MALDI MSI-based method was developed to locate the distribution of substances in xylem accurately,which greatly promotes the understanding of the biomarker parent and broadens the thinking for the study of biomarker.