Introduction of mass spectrometer - basic types of ion source
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The document provides an overview of mass spectrometry, detailing various ionization methods such as Electron Ionization (EI), Chemical Ionization (CI), Atmospheric Pressure Chemical Ionization (APCI), Electrospray Ionization (ESI), and Matrix-Assisted Laser Desorption/Ionization (MALDI). Each method is described in terms of its processes, applications, and the types of samples suitable for analysis. The information serves as a foundational introduction to mass spectrometer components and ionization techniques.
Introduction of mass spectrometer - basic types of ion source
- 1. Introduction of mass spectrometer Presented by Creative Proteomics www.creative-proteomics.com basic types of ion source
- 2. Inlet System Ion source Mass Analyzer Detector Data System The general components of mass spectrometry
- 3. Basic types of ion source Electron Ionization(EI) Chemical Ionization (CI) Atmospheric Pressure Chemical Ionization(APCI) Electrospray Ionization (ESI) Matrix-Assisted Laser Desorption/Ionization (MALDI)
- 4. Electron Ionization(EI) • Relatively molecule weight is below 600 • When a molecule passes this high energy electrons beam, an electron can be expelled from the molecule to produce an ion. • Gas chromatography (GC) is the most widely used method in EI-MS for sample insertion. • EI causes extensive fragmentation M M M M+ M+ M+ Filament Collector to mass analyzer N S Magnet Magnet
- 5. • CI is a lower energy process than electron ionization. • Ions are produced by the collision of the samples with ions of a reagent gas that are present in the ion source. • Sample ions are produced by the ion-molecule reactions of reagent gas ions and sample molecules • Some common reagent gases include methane, ammonia and isobutene. Chemical Ionization (CI) N S M M MM M M M M+ MH+ M+ M+ MH+ M+ M+ MH+ Magnet Magnet Filament to mass analyzer R R R R R R R R R R R R RR Trap
- 6. Atmospheric Pressure Chemical Ionization(APCI) Corona Discharge Electrode to mass analyzer Heater Nebulizer Gas Skimmer + + + • APCI is a method which creates ions at atmospheric pressure, commonly coupled with high-performance liquid chromatography (HPLC) • This ionization method is appropriate for relatively polar and semi-volatile samples • Consist of a nebulizer probe which can be heated, an ionization region with a corona discharge needle and an ion-transfer region. Analyte Flow
- 7. • ESI is a soft ionization technique, which is useful for biological molecules of large molecular mass • Generate highly charged droplets directly from the infused solution • Desolvation gas is applied to the charged droplets to reduce the size of droplets. • The droplet fission leads to the formation of individual gas phase analyte ions Electrospray Ionization (ESI) +++ +++ +++ +++ + + + + + Solvent evaportion Columbic repulsion Power supply Sample Solution Charged droplets Charged ions Rayleigh limit Nebulization gas(N2)
- 8. • A technique to allow the high molecular weight compounds into the gas phase as intact ions • The mechanism of MALDI consists of three processes: mixture, matrix excitation, analyte ionisation • The time-of-flight (TOF) analyzers are always used with the MALDI ionization source. Matrix-Assisted Laser Desorption/Ionization (MALDI) to mass analyzer + + + + + + + + + + + + + Laser beam Matrix spots Sample plate Extraction grid Analyte spots
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