The mass spectometer

What does the mass spectrometer do

Determines the relative atomic mass

Relative atomic mass formula

(Isotope mass • abundance) / total abundance

What happens in a time flight mass spectrometer

Ionisation

Acceleration

Ion drift

Detection

Data analysis

Why is apparatus under vacuum

Prevents the ions from colliding with air

Ionisation

Positive terminal of high voltage produces tiny positively charged droplets which have lost electrons

The solvent evaporates until only ions are left

Acceleration

Positive ions are attracted towards a negatively charged electric plate causing them to accelerate

Ions drift

Ions with the same kinetic energy pass through a series of holes in the negatively charged plate

This forms a beam along the flight tube

How is velocity of ions found

Time taken the ion to drift

Kinetic energy of ions formula

½ MV²

Detection

Positive ions hit the detector and gain an electron causing current to flow