MASS SPECTROMETER

Question 1

what is relative atomic mass

Answer 1

average mass of an atom relative to 1/12 mass of an atom of carbon12

Question 2

what are the 4 stages of the mass spectrometer

Answer 2

ionisation
acceleration
ion drift
ion detection

Question 3

describe method 1 of ionisation

Answer 3

sample bombarded by high energy electrons
particles lose an electron to form positive ions

Question 4

describe the second method of ionisation

Answer 4

electrospray ionisation
sample dissolved in a volatile solvent
injected through positively charged needle
each particle gains a proton

Question 5

describe acceleration stage in a mass spectrometer

Answer 5

positive ions accelerated by an electric field
potential energy = qV
all the ions are given the same kinetic energy

Question 6

describe ion drift stage in a mass spectrometer

Answer 6

lighter ions move with higher velocity so reach the detector first

Question 7

describe the ion detection stage in a mass spoectrometer

Answer 7

ion gains an electron from the detector
creates a current
abundance proportional to current

Question 8

what does the detector record in a mass spectrometer

Answer 8

1. time taken for the ion to reach it
2. current