经典生物质谱课件剖析.ppt

Mass Spectrometry for Biotechnology  1 质谱仪的概念？ Mass Spectrometry:A method to “weigh” molecules Definition An analytical device that determines the molecular weight of chemical components(and obtains structural information) by separating molecular(and product) ions according to their m/z; 能使物质粒子离子化并根据其质荷比（m/z）不同，通过适当的电场、 磁场将它们按空间、时间先后或者轨道稳定与否进行分离并检测强度后进行物质分析的仪器。质谱的重要特点之一是检测物质的离子的质/荷比。 Preface and Introduction(3) Chapter 1 Ion Sources and Sample Introduction Unit 1 Sample Introduction methods for sample introduction: *use of insert probe; *capillary infusion; including(in fact): GC,LC,Syringe pump,needle ,etc. Unit 2 Ionization Techniques(1) Most common ionization methods: *electron ionization,EI *fast atom/ion bombardment,FAB *matrix-assisted laser desorption/ionization,MALDI *electrospray ionization,ESI Unit 2 Ionization Techniques(2) 1.Electron Ionization,EI use electron with certain energy impact on the sample and make them ionized.(electron impact) Unit 2 Ionization Techniques(3) Key notes: 1)Sample is delivered as a gas ;(involving in thermal desorption or “boiling off” the sample from the probe) 2)limited mass range ;(due to the thermal desorption (volatility) requirement) 3)principal problems in analysis of large biomolecules: difficult to volatilize(nonvolatile),thermal decomposition,excessive fragments(in many cases); Unit 2 Ionization Techniques(4) 2.Fast Atom/ion Bombardment(FAB) 1)use a high-energy beam of Xe atoms,Cs ions,or massive glycerol-NH4+ clusters to sputter the sample and matrix from the probe surface into the gas phase. 2)The sample may be already charged or it may become charged through reactions with surrounding molecules or ions. 3)The ionization reaction primarily make sample protonized and form MH+. Unit 2 Ionization Techniques(5) 3、M