2.8 Instrumental Analysis

Learn how to use mass spectra in identification of chemical structure. Use infra red spectra to identify chemical structure. Use of H NMR spectra to identify chemical structure.

Vapourisation

Sample is heated until particles become gaseous.

Ionisation

Particles are bombarded with a stream of electrons, electrons are knocked off and atoms become ions.

Acceleration

An electric field accelerated positive ions to high speed.

Deflection

Different ions are deflected by an electromagnet depending on their mass/charge.

Detection

The beam of ions passing through the machine are detected. Only 1+ ions will make it through the machine.

Fragmentation

Molecular ion fragments form due to covalent bonds breaking.

Molecular ion peak

• Peak with the highest M/Z ratio represents the molecular ion, and gives the Mr of compound.

Base peak

• The tallest peak is the most abundant ion.