The Research On Key Technologies Of Matrix-assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometer

With the rapid development of science and technology and the progress of society,the analysis of proteins,nucleic acid research as well as the identification of microorganisms has increasingly shown their importance in the field of life science.Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry(MALDITOFMS)is an ideal tool for them.In recent years,this technology has been rapidly developed and widely used.In order to guide its design and better optimize the performance of MALDI-TOFMS,the key technologies of the instrument,such as ion generation,extraction,transmission,screening and detection,were studied thoroughly in this paper.There is no unified theoretical model for matrix-assisted laser desorption ionization.From the perspective of establishing ionization model and optimizing ion source performance,this paper designed and built a laser parameter test platform,tested the relevant parameters of the laser,and studied the relationship between the laser energy density and the effect of ionization.In addition,the matrix and sample concentration ratios were optimized by evaluating the laser energy intensity threshold that triggered the ionization,the laser energy intensity of the triggered ionization was calculated in the meantime.Ion extraction,transmission and selection require precise timing control.The SIMION 3D ion optical simulation software was used to simulate and calculate the working timing sequence of time-of-flight mass spectrometry(TOFMS)and then the theoretical calculation model of TOFMS working timing sequence would be established.Based on simulation results,the MALDI-TOFMS ion focusing device and ion screening device were developed.The theoretical calculation and simulation model were discussed using polypeptide mixture samples.The sequence control of delay extraction,ion gate,low mass gate as well as the optimization strategy of ion transport system were proposed to effectively improving the analytical performance of the instrument.