chem 1:1 relative mass and the mass spectrometer

What is the relative atomic mass

The average mass of an atom of an element

What is the relative isotopic mass

The mass of an atom of an isotope of an element

What is the relative molecular mass

The average mass of a molecule

What does a mass spectrometer measure

Relative masses

What is the first step in using a mass spectrometer

Ionisation

What are the ways to perform ionisation

Electrospray ionisation and electron impact ionisation

How to perform electrospray ionisation

Sample is dissolved and pushed through a small nozzle at high pressure and a high voltage is applied causing each particle to gain a H+ ion leaving a gas of positive ions

How is electron impact ionisation performed

Sample is vaporised and an electron gun is used to fire high energy electrons at is so one electron is knocked of each particle leaving 1+ ions

Acceleration is the second step of using a mass spectrometer what happens in this step

The positively charged ions are accelerated by an electric field so they all have the same kenetic energy. This means lighter ions will move faster than heavier ions

Ion drift is the third step in using a mass spectrometer what happens in this step

Ions enter a region with no electric field so they just drift and lighter ions will continue to drift faster than heavier ions

As the lighter ions travel faster they will reach the ion detectors first, what is produced from this data

Mass spectrum

On a mass Spectrum what is shown on the y axis

Abundance of ions

On a mass Spectrum what is shown in the x axis

Mass/charge (m/z)

What is the format of a mass spectrometry

A table

What can mass spectrometry be used for

To identify molecules