Chemistry - TOF mass spectrometer
0.0(0)
Studied by 0 people
Learn
Practice Test
Spaced Repetition
Match
FlashcardsCard Sorting
1/16
There's no tags or description
Looks like no tags are added yet.
Study Analytics
Name | Mastery | Learn | Test | Matching | Spaced |
|---|
No study sessions yet.
17 Terms
1
New cards
the relative charges of protons electrons and neutrons are
positive for protons, negative for electrons, and neutral for neutrons.
2
New cards
the relative masses of protons electrons and neutrons area
1 for protons and neutrons, 1/2000 for electrons
3
New cards
an isotope is an atom/molecule of…
the same element, with the same number of protons but different number of neutrons
4
New cards
and ion is an atom/molecule…
that carries a + or - charge due to loss or gain of electrons
5
New cards
What does TOF mass spectrometer do?
detects the mass and relative abundance of isotopes
6
New cards
How can mass spectrosopy be used?
to identify elements
to determine RAM
to determine RAM
7
New cards
Three stages during TOF mass spectroscopy
Ionisation
Acceleration
detection
(data analysis)
Acceleration
detection
(data analysis)
8
New cards
What are the two methods of ionisation?
Electron impact
Electrospray
Electrospray
9
New cards
How does ionisation using electron impact work?
* Sample heated to vapourise it
* sample gets bombarded with electrons from electron gun
* X + e- → X+ + 2e-
* (electron fired at sample and knocks off one other electron, to form 1+ ions)
* sample gets bombarded with electrons from electron gun
* X + e- → X+ + 2e-
* (electron fired at sample and knocks off one other electron, to form 1+ ions)
10
New cards
How does ionisation using electrospray work?
* dissolve sample in volatile solution
* inject through a fine, + charged needle to produce a fine spray
* particles gain a proton from charged needle
* solvent evaporates, leaving 1+ ions
* H+ is gained from the solvent ( X + H+ → XH+ )
* inject through a fine, + charged needle to produce a fine spray
* particles gain a proton from charged needle
* solvent evaporates, leaving 1+ ions
* H+ is gained from the solvent ( X + H+ → XH+ )
11
New cards
Why are two types of ionisation used?
Electron impact → for elements and low Mr compounds
Electrospray → used for high Mr compounds
Electrospray → used for high Mr compounds
12
New cards
What happens during the acceleration stage?
* charged plate creates a magnetic field to attract ions
* all ions accelerated, have same kinetic energy
* have different velocities due to different masses and charges of ions
* ION DRIFT → ions travel through charged plate and along flight tube
* all ions accelerated, have same kinetic energy
* have different velocities due to different masses and charges of ions
* ION DRIFT → ions travel through charged plate and along flight tube
13
New cards
What happens during the detection stage?
* negatively charged detector (full of electrons) met by lightest ions first
* + ions gain electrons
* this causes an electric current to flow
* + ions gain electrons
* this causes an electric current to flow
14
New cards
What two equations are used in TOF calculations?
EK= half mv squared
t= d/s
t= d/s
15
New cards
16
New cards
why are charged plates used to accelerate ions
opposite charges attract
17
New cards