Mass Spectrometer Flashcards
(3 cards)
What happens in a time of flight mass spectrometer?
Ionisation is the first stage the gaseous sample is hit with electrons from the electron gun and an electron is knocked out making them positive gaseous ions. Next is acceleration where the positive plate at -200 and the negative plate at -600 create an electric field. As the ions enter the drift region they will all be moving with different speeds hence they will be separated in the drift region depending upon their m/z ratio, smaller m/z ratio ions will have a shorter time of flight. (5)
What is the relative atomic mass?
The average mass of an atom of an element compared to 1/12th the mass of carbon 12.
Why is Carbon 12 used rather than Hydrogen?
Carbon 12 is the standard by which all other atoms are measured because it is a solid and is easier to handle then hydrogen and the Carbon 12 isotope can be isolated.
