As we know before, the mass spectrometry consists of three main components, the ion source, the mass analyzer, and the detector. In ion source, a sample is ionized. Today, we are going to introduce several types of ion source, which are usually used in a mass spectrometry.

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

9. Our Information
www.creative-proteomics.com
45-1 Ramsey Road, Shirley, NY 11967, US
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