This document provides an overview of mass spectrometry. It discusses the brief history of mass spectrometry from 1913 to 2002. It then summarizes the basic principles and components of mass spectrometers, including sample inlet systems, ion sources like electron impact and electrospray ionization, mass analyzers like quadrupole and time-of-flight, detectors, and applications in fields like pharmaceuticals, clinical work, environment and biotechnology. The document aims to introduce readers to mass spectrometry through examining its origins, instrumentation, and uses.

1. Presentation on:-
Mass Spectrometry
Presented by :- Vipin Jain
M.Sc.(Pharmaceutical
Chemistry) 2ndsem

2. Contents:-
1) Brief History of mass spectrometry
2) Introduction
3) Basic Principle
4) Instrumentation
5) Mass Spectrum
6) Applications

3. Brief History of mass spectrometry
1913:- Thomson separates the 20Ne and the 22Ne isotopes, and he correctly
identifies the m/z = 11 signal as a doubly charged 22Ne particle.
1919:-Francis Aston constructs the first velocity focusing mass spectrograph.
1934:-Josef Mattauch and Richard Herzog develop the double-focusing mass
spectrograph.
1946:-William Stephens presents the concept of a time-of-flight mass
spectrometer.
1968:-Malcolm Dole develops electrospray ionization.
2002:- John Bennett Fenn and Koichi Tanaka are awarded the Nobel Prize in
chemistry "for the development of soft desorption ionisation methods for
mass spectrometric analyses of biological macromolecules."

4. Introduction:-
Mass spectrometry is a powerful analytical technique
used to identify unknown compounds within a sample,
and to elucidate the structure and chemical properties of
different molecules.
The complete process involves the conversion of the
sample into gaseous ions, with or without fragmentation,
which are then characterized by their mass to charge
ratios (m/z) and relative abundances.

5. Basic Principle:- A mass spectrometer generates multiple ions from the
sample under investigation, it then separates them according to their
specific mass-to-charge ratio (m/z), and then records the relative
abundance of each ion type.
A mass spectrometer needs to perform three functions:-
• Creation of ions – the sample molecules are subjected
to a high energy beam of electrons, converting some
of them to ions.
• Separation of ions – as they are accelerated in an
electric field, the ions are separated according to
mass-to-charge ratio (m/z).
• Detection of ions – as each separated population of
ions is generated, the spectrometer needs to qualify
and quantify them.

6. An instrument that generates ions from molecules and measure their
masses.
The essential components of mass spectrometers:-
SAMPLE
INLET
ION
SOURCE
ION
ACCELERATOR
ION
ANALYSER
ION
DETECTOR
signal
COMPUTERMASS SPECTRUM
0
50
100
0 10 20 30 40 50 60 70 80
2
15
27
41
53
69
84
1-Butene, 3,3-dimethyl-
Instrumentation:-

7. Sample Inlet System:-
The purpose of the inlet system is permit introduction of a
representative sample into the ion source with minimal loss of
vacuum.
Most modern mass spectrometers are equipped with several types of
inlets to accommodate various kinds of sample ,these include:
1- Batch Inlet System ( Gas+ some liquid)
2- The Direct Probe Inlet ( Solid+ Liquid)
3- Chromatography and Capillary Electrophoretic Inlet System.

8. Ion Source:- For producing gaseous ions from the substance being
studied.
Ways to produce ions:-
1) Electron impact (EI) - vapor of sample is bombarded with
electrons.
M + e ==== 2e + M.+ + fragments
2) Chemical ionization (CI) - sample M collides with reagent ions
present in excess e.g.
CH4 + e ===== CH4
.+ + CH5
+
M + CH5
+ ==== CH4 + MH+
3) Fast Atom/Ion Bombardment (FAB):- Ionisation is brought by
fast moving atoms.
4) Electrospray Ionization (ESI) - a stream of solution passes
through a strong electric field (106 V/m).

9. The Electron-Impact Source:-

10. High Energy electrons 
Sample Molecule MH

CH4
CH4 CH4
+ CH3
+ CH2
+
25243
3544
HHCCHCH
CHCHCHCH




6252
42252
425
HCMMHHC
HCMHMHHC
CHMHMHCH






Molecule Ions


11. Fast atom bombardment

12. Electrospray Ionisation

13. Electrostatic Acceleration System:-
1) The positive ions formed in the ionisation chamber are
withdrawn by the electric field which exists between the first
accelerator plate and the second repeller plate.
2) A strong electrostatic field between accelerator and repeller
plate accelerates the ions of masses m1 m2 m3... to their final
velocities.
3) The ions which escape through slit having velocities and
kinetic energies give.
eV=1/2m1v1
2=1/2m2v2
2=1/2m3v3
2......

14. Vacuum system:-
1) A high vacuum is to be maintained.
2) The inlet system is generally maintained at 0.015 torr, the ion
source at 10-15 torr and analyzer tube at 10-7 torr or as low as
possible.
3) Oil diffusion and mercury diffusion pumps are commonly used
in different types of combination

15. Mass analyzers:-
1) Separate ions based on their mass-to-charge ratio (m/z)
2) Operate under high vacuum (keeps ions from bumping into gas
molecules)
3) Actually measure mass-to-charge ratio of ions (m/z)
Types of mass analyzers:-
1) Quadrupole mass analyzer
2) Time of flight analyzer (TOF)
3) Magnetic sector mass analyzer
a) Single focusing
b) Double focusing
4) Quadrupole ion trap mass analyzer

16. Quadrupole mass analyzer:-
1) It consists of 4 voltage carrying rods.
2) The ions are pass from one end to another end
3) During this apply the radiofrequency and voltage complex oscillations will
takes place.
4) Here the single positive charge ions shows the stable oscillation and the
remaining the shows the unstable oscillations

17. Magnetic Sector Mass Analyzer:-
In magnetic sector analyzers ions are accelerated through a flight tube,
where the ions are separated by charge to mass ratios.
m/z = B2 R 2 / 2V

18. Time of flight analyzer:-

19. Detector:-
1) Electron multiplier:- Electron multipliers use a process known as secondary
electron emission.
2) Faraday cup:- A Faraday cup is a metal (conductive) cup designed to
catch charged particle in vacuum.

20. The mass spectrometer:-

21. Mass, as m/z. Z is the charge, and for doubly charged ions (often seen in
macromolecules), masses show up at half their proper value
molecular ion
Unit mass
spacing
Fragment Ions
Derived from
molecular ion
or higher
weight
fragments
Mass Spectrum:- A plot of the relative abundance of ions
versus their mass-to-charge ratio (m/z).

22. Mass spectrum of propane:-

23. Applications:-
1) Pharmaceutical: drug discovery, combinatorial chemistry,
pharmacokinetics, drug metabolism.
2) Clinical: neonatal screening, haemoglobin analysis, drug testing.
3) Environmental: PAHs, PCBs, water quality, food contamination.
4) Geological: oil composition.
4) Biotechnology: the analysis of proteins, peptides.

24. References:-
• Instrumental methods of chemical analysis by G.R.Chatwal
• www.omicsonline.org/mass-spectrometry
• wikipedia.org/wiki/Mass_spectrometry
• www2.chemistry.msu.edu
• www.chemguide.co.uk