Mass Spectrometry Flashcards
What are the uses of Mass Spectrometry?
It is used to calculate the natural abundance of isotypes and to identify the composition of mixtures.
What is Stage 1 of Mass Spectrometry?
Vaporisation: a sample of the chosen element is vaporised in a vacuum chamber then passed in to the mass spectrometer (solid –> gas)
What is Stage 2 of Mass Spectrometry?
Ionisation: sample passes through a high energy electron beam where the collisions within the beam cause the gaseous atoms to lose one of their electrons (forms +1 ions and a few +2 ions)
What is Stage 3 of Mass Spectrometry?
Acceleration: resulting ions are accelerated by an electric field to form a high speed beam of positive ions that is directed through a strong magnetic field.
What is Stage 4 of Mass Spectrometry?
Deflection: individual ions become deflected by the filed and move into circular paths of different radius depending on their mass and charge. Ions of lower mass experience more deflection by the magnetic field.
What is Stage 5 of Mass Spectrometry?
Detection: measures the intensity and radius of deflection of each of the ion beams. The detector count is a measure of the isotype abundance and the degree of beam reflection is related to the isotopic mass. Resulting data can be tabulated/displayed as a mass spectrum of the sample.
What is the Relative Atomic Mass Equation?
(percentage abundance of isotype x isotype mass number)/100
How are different particles deflected?
Heavier –> Less, Lighter –> More
How are different charges deflected?
Higher –> More, Lower –> Less
