Tandem in space and tandem in time

1. TANDEM MASS SPECTROMETRY
(MS-MS)
Dr. Tambe Vrushali Sachinkumar
PES Modern College of Pharmacy (For Ladies), Moshi

2. Structural elucidation tool
Tandem mass spectrometry, also known as MS/MS or MS2, is a
technique in instrumental analysis where two or more mass
analyzers are coupled together using an additional reaction
step to increase their abilities to analyse chemical samples.
A common use of tandem-MS is the analysis of biomolecules,
such as proteins and peptides.
Types
1. Tandem in time
2. Tandem in space

3. Tandem in Time
Analyte
Ion
Select Parent ion
for fragmentation
Generation of daughter
ions
Analysis
Detection
MSn
1000
500 400 900 600 700
MS1
360 750 850 500 700
MS2
360 450 600 400 700
MS3
In the same space, fragmentation
of selected ions is carried out
subsequently number of times

4. • A quadrupole ion trap or Fourier transform
ion cyclotron resonance (FTICR) instrument
can be used for such an analysis.

5. Tandem in Space
Physically different units are present
The molecules of a given sample are ionized and the first spectrometer (designated MS1)
separates these ions by their mass-to-charge ratio. Ions of a particular m/z-ratio coming
from MS1 are selected and then made to split into smaller fragment ions, e.g. by collision-
induced dissociation, ion-molecule reaction, or photodissociation. These fragments are
then introduced into the second mass spectrometer (MS2), which in turn separates the
fragments by their m/z-ratio and detects them. The fragmentation step makes it possible
to identify and separate ions that have very similar m/z-ratios in regular mass
spectrometers.
soft ionization source

6. • Collision activated dissociation (CAD)/ Collosion
induced dissociation (CID)
Energy can also be added to the ions, which are
usually already vibrationally excited, through post-
source collisions with neutral atoms or molecules
• Electron capture dissociation (ECD)
An electron is transferred to or captured by a
multiply charged ion releases energy which can
induce fragmentation.

7. • Photodissociation (PID)
The energy required for dissociation can be added
by photon absorption, resulting in
ion photodissociation.
Ultraviolet lasers can be used, but can lead to
excessive fragmentation of biomolecules.
• Surface induced dissociation
With surface-induced dissociation (SID), the
fragmentation is a result of the collision of an ion
with a surface under high vacuum.

8. Ion Source
Mass
Analyser 1
Interaction
Cell
Mass
Analyser 2
Detector
ABCD+
XYZ+
ABCD+
Presursor
ion
AB+, CD+, BC+
Product ions
The product-ion spectrum can be obtained by scanning mass analyzer 2,
while mass analyzer I is held constant, acting as a mass selector to select
one precursor ion. (the product-ion spectra of the two compounds are
very different)
MS-MS Modes

9. A precursor ion spectrum can be obtained, by scanning the first mass
analyzer while holding the second mass analyzer constant to detect a
given product ion. In a mixture of compounds, those that give the
same products are readily identified by precursor ion spectra.
Ion Source
Mass
Analyser 1
Interaction
Cell
Mass
Analyser 2
Detector
ABCD+
BCDF+
DFG+
All
Presursor
ion
CD+
Product ions

10. Neutral loss spectrum: By scanning both analyzers
simultaneously with an offset in mass between them. This gives
the identity of those precursor ions that undergo the same loss
such as the loss of a H20 or CO neutral.
Ion Source
Mass
Analyser 1
Interaction
Cell
Mass
Analyser 2
Detector
600 m/z All
Presursor
ion
Product ions
582 m/z

11. A complete three dimensional MS/MS spectrum:
By scanning mass analyzer 1 and obtaining the
product-ion spectrum for each selected precursor
ion.

12. • Selected/Multiple Reaction Monitoring
selects for known, well characterized ions only
Selected reaction monitoring (SRM) is a method used in tandem mass
spectrometry in which an ion of a particular mass is selected in the
first stage of a tandem mass spectrometer and an ion product of a
fragmentation reaction of the precursor ion is selected in the second
mass spectrometer stage for detection.
Used for Quantitative analysis

13. Types of arrangements
1. Electric sector with a magnetic sector
spectrometer
(in forward geometry electric sector is followed by magnetic sector, or EB)
(in reverse geometry magnetic sector is followed by electric sector, or BE). The reverse
geometry is called a mass-analyzed ion kinetic energy spectrometer (MIKES).
2. BEqQ spectrometer (magnetic sector, B; electric
sector, E; RF-only quadrupole, q; quadrupole mass
analyzer, Q)
3. BTOF (magnetic sector, B; TOF analyzer)
4. QqTOF
5. triple quadrupole (QqQ)
6. ion-trapTOF
7. TOF-TOF spectrometer

14. Thank You….