1911130
Description
Mind Map by Pia Ricioppo, updated more than 1 year ago
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Created by Pia Ricioppo
over 9 years ago
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mass spectrometry
- ionisation
- the samples hit with a high energy stream of electrons from the electron gun.
- these electrons 'knock off' the
electrons in the outer shell.
- this causes the atom of
molecule to form a postivly
charged ion
- this causes the atom of
molecule to form a postivly
charged ion
- these electrons 'knock off' the
electrons in the outer shell.
- IF the electron from the
electron gun has a high
enough energy ANOTHER
electron will be removed
- this causes a doubly charged ion
- eg;
- eg;
- this causes a doubly charged ion
- the samples hit with a high energy stream of electrons from the electron gun.
- heres the
basic
principle;
- ACCELERATIOn
- ions are now accelerated by an electric
field caused by the positive charged plates.
- the slits in the plates narrow the beam
- the ions are accelerated towards the magnetic field.
- the rate at which they're accelerated
is proportional the the m/z ratio.
- the rate at which they're accelerated
is proportional the the m/z ratio.
- the ions are accelerated towards the magnetic field.
- the slits in the plates narrow the beam
- ions are now accelerated by an electric
field caused by the positive charged plates.
- deflection
- accelerated ions are deflected by an
electromagnetic field
- for each ion the degree of deflection depends on the m/z ratio
- DEFLECTIONS GREATER IF
- the mass of the ions smaller
- the charge of the ions greater
- the strength of the field greater
- the mass of the ions smaller
- DEFLECTIONS LESS IF;
- the mass of the ions larger
- charged of +ve ions lower
- the strength of
magnetic fields
less
- the mass of the ions larger
- DEFLECTIONS GREATER IF
- for each ion the degree of deflection depends on the m/z ratio
- accelerated ions are deflected by an
electromagnetic field
- detection
- as an ion reaches a
detector it produce a
tiny current.
- the number of electrons
realised and the current
produced is proportional to the
number of ions striking the
detector
- the detectors linked to an amplifier
- then to a recorder
which converts the
current into a peak
which is shown on
mass spectrum.
- then to a recorder
which converts the
current into a peak
which is shown on
mass spectrum.
- the detectors linked to an amplifier
- the number of electrons
realised and the current
produced is proportional to the
number of ions striking the
detector
- as an ion reaches a
detector it produce a
tiny current.
- interpreting the mass spectra;
- mass spectra are graphs which give info about each ion produced in the sample
- it shows m/z ratio of each ion
- shows abundance of each ion
- infos used to work out relative atomic mass
- it shows m/z ratio of each ion
- mass spectra are graphs which give info about each ion produced in the sample
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