There are two methods of ionisation in a time of flight spectrometer, name and explain one of these methods in detail.

1).Electron impact ionisation- in this types of ionisation the sample is vaporised and injected into the mass spectrometer, then high energy electrons are fired at this sample from an electron gun. This knocks off one electron from each particle of the sample forming a positive ion. OR 2).Electrospray Ionisation- in this method the sample is dissolved in a volatile solvent e.g. water and injected through a fine hypodermic needle to give a fine mist. The tip of the needle is attached to the positive terminal of a high voltage power supply. The particles from the sample become ionised by gaining a proton.