U1S1- Mass Spectrometer

Question 1

Electrospray ionisation

Answer 1

The sample is dissolved in a solvent and pushed through a nozzle at high pressure. A high voltage is applied, causing the particles to gain a H+ ion. The solvent is then removed, leaving a gas of positively charged ions.

Question 2

Electron impact ionisation

Answer 2

The sample is vaporised and an ‘electron gun’ fires high energy electrons at it. This knocks one electron off creating a charged ion.

Question 3

Acceleration

Answer 3

The charged ions are passed through an electric field. The electric field gives the same kinetic energy to all of the particles. The lighter ions experience a greater acceleration so they spend less time in the TOP mass spectrometer.

Question 4

Ion drift

Answer 4

The ions enter the area with no electric field. The drift through it a the same speed as they did in the electric field.

Question 5

Detection

Answer 5

The lighter ions are detected here first.

Question 6

Relative isotopic abundance

Answer 6

The relative amount of each isotope present in a sample.