Development Of Graphene-based MALDI-TOF Mass Spectrometry Methods And Their Applications For The Detection Of Small Molecule In Complex Media

Graphene was used as a matrix in matrix-assisted laser desorption/ionization time-of-flight mass spectroscopy(MALDI-TOF MS)for detection of small molecules in complex media in this thesis.Due to the high surface area of graphene,analytes could be trapped tightly to the matrix,which avoids the contamination of ion source or vacuum system.Furthermore,the excellent electronic and optical properties improved the efficiency of desorption/ionization of analytes on graphene matrix.Compared with conventional matrices,graphene could provide advantages such as reduced interference from background matrix ions,good reproducibility,high salt tolerance,high resolution and high sensitivity.In summary,graphene-based MALDI-TOF MS provided a simple,sensitive,fast,cost-effective and high-throughput technique for analysis of low-mass molecules.This thesis is divided into three chapters.In Chapter 1,MALDI-TOF MS including the basic principle and its features were introduced.The applications of graphene as a matrix for the analysis of various compounds in MALDI-TOF MS were summarized.Finally,the purpose and main content of this thesis were proposed.In Chapter 2,an antibody-graphene oxide nanoribbon conjugate(GONR-PEG-Ab)was prepared and its application in SELDI-TOF MS analysis was studied.Graphene oxide nanoribbons(GONRs)were prepared through unzipping of multiwall carbon nanotubes and then were covalently functionalized with antibody using polyethylene glycol(PEG)to be used as a specific SELDI probe.GONR-PEG-Ab probe were characterized and applied to analyze chloramphenicol in complex media.This new probe provides a highly sensitive and selective platform for enrichment and MS detection of small molecules in complex media.In Chapter 3,a high-throughput detection method for small molecules in complex media using graphene as a MALDI-TOF MS matrix combined with ordered mesoporous carbon as an enrichment material was developed.CMK-3,CMK-8,SBA-15,and MCM-41 were compared for the extraction of small molecules in complex media,and it is found that CMK-8 showed the best enrichment performance.This method was applied to detect PFOS,PFHxS and PFBS successfully in serum samples from workers in a perfluorochemical plant.