instrumentation of mass spectroscopy by Ameer Hamza

2. • Mass spectrometery is an instrumental
technique in which sample is converted to
rapidly moving positive ions by electron
bombardment and charge particales are
separated according to their masses

4. • 1 Sample Inlet
• 2 Ionization
• 3 Accelration
• 4 Deflection
• 5 Detection

5. • Sample stored in a large reservoir from
which molecule reaches the ionization
chamber at low pressure in the steady
stream by by a pinhole called “Molecular
Leak”

6. • The atom is ionised by knocking one or
more electrons off to give a positve
ion.(Mass spectrometer work with always
positve ions)
• Most of the positve ions formed will carry a
charge of +1

7. • The particals in the sample (atom or
molecule) are bombarded with a streem of
electrons to knock one or more electrons out
of the sample particals to make positve ions

8. The positve ions are persuaded out in to the
rest of the machine by the ions repeller
whichis an other metal plate carrying a slight
positve charge.
Ionization can be achieved by
§ Electron Ionization
§ chemical ionization
§ Desorption ionization

9. • The ions are accelrated so that they have
the same the kinetic energy

10. • The positve ios are repelled away from the
positve ionization chamber and pass
through three slit with voltage in the
decreasing order
• The middle slit carries some intermediate
voltage and the final at “ 0” volt
• All the ions are accelrated into a finely
focused beam

11. • The ions are then deflected by a magnatic
field according to their masses.The lighter
they are the more it get are deflected
• The amount of deflection also depend on
the number of positve charges on the
ion.The more the ions is charged the more
it gets deflected

13. • Different ions are deflected by the
magnatic field by different amounts.The
amount of deflection depends upon.

14. • The beam of ions passing through the
machine is detected electrically

16. • When an ion hits the metal box its charge
is neutralised by an electron jumping from
the metal on to the ion
• That leaves a space amongst the
electrons in the metal and the electrons in
the wire shuffle along to fill it

17. • A flow of electrons in the wire is detected
as an electric current which can be
amplified and recorded .The more ions
arriving the greater the current