Time of flight mass spectrometry by Heather Haywood https://padlet.com/heatherhaywood/vtyledqiqli2 Chemistry 1.1 en-us 2017-10-10 09:52:24 UTC 2017-10-10 10:21:52 UTC hello@padlet.com What is mass spectrometry used for heatherhaywood https://padlet.com/heatherhaywood/vtyledqiqli2/wish/195507468 • Find the abundance and mass of each isotope in an element allowing us to determine its relative atomic mass
• Find the relative molecular mass of molecules]]> 2017-10-10 09:57:07 UTC https://padlet.com/heatherhaywood/vtyledqiqli2/wish/195507468 Stage 1- Ionisation(Electron impact) heatherhaywood https://padlet.com/heatherhaywood/vtyledqiqli2/wish/195508048 • The sample is vaporised
• High energy electrons are then fired at it from an 'electron gun'
•This knocks off one electron from each oarticles forming a 1+ ion.
• The 1+ ions are then attracted towards a negative electric plate where they are accelerated]]> 2017-10-10 09:59:24 UTC https://padlet.com/heatherhaywood/vtyledqiqli2/wish/195508048 Electrospray ionisation heatherhaywood https://padlet.com/heatherhaywood/vtyledqiqli2/wish/195509154 •The sample is dissolved in a volatile solvent 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 are ionised by gaining a proton from the solvent as they leave needle producing H+ ions.
•The solvent evaporates away while the ionised sample is attracted towards a negative plate where they are accelerated.
*** Fragmentation rarely takes place

]]> 2017-10-10 10:04:08 UTC https://padlet.com/heatherhaywood/vtyledqiqli2/wish/195509154 Stage 2- Acceleration heatherhaywood https://padlet.com/heatherhaywood/vtyledqiqli2/wish/195510415 The positive ions are accelerated using an electric field so that they all have the same kinetic energy.
• The velocity of each particle depends on its mass]]> 2017-10-10 10:10:50 UTC https://padlet.com/heatherhaywood/vtyledqiqli2/wish/195510415 Stage 3- Flight tube heatherhaywood https://padlet.com/heatherhaywood/vtyledqiqli2/wish/195511088 • The positive ions travel through a hole in the negatively charged plate into a tube.
• The time of flight of each particle through this flight tube depends on its velocity which in turn depends on its mass]]> 2017-10-10 10:12:47 UTC https://padlet.com/heatherhaywood/vtyledqiqli2/wish/195511088 Stage 4- Detection heatherhaywood https://padlet.com/heatherhaywood/vtyledqiqli2/wish/195511540 Positive ions generate a current when they hit the detection plate.
• The size of the current generator is proportional to the abundance of the ion]]> 2017-10-10 10:14:56 UTC https://padlet.com/heatherhaywood/vtyledqiqli2/wish/195511540