Mass Spectometry

• What is the abundance?


  How common each isotope is.
• What is a mass spectrometer?


  An instrument that determines the mass number ans abundance number of isotopes.
• What is the first step of mass spectometry?


  The sample is taken into the sample chamber, this contains all of the different isotopes of the element.
• What is the second step of mass spectometry?


  Atoms go through ionisation, which is where the atoms are converted into positive ions.
• What does the ionisation process allow?


  It allows the ions to be attracted to the negatively charged plate.
• What is the third step of mass spectometry?


  The negatively charged plate causes the ions to accelerate, increasing the kinetic energy of the ions.
• What happens after the third step of mass spectrometry?


  Once the ions pass through the negatively charged plate, they stop accelerating and drift down the chamber to the detector.
• What is the forth step of mass spectometry?

  The ions drift down the chamber at different velocities with lighter ions moving faster than heavier ions.
• What is the last step of mass spectrometry?


  The ions then reach the detector, each positive ion gains an electron from the detector, causing a current to flow.
• What does the time taken to move down to the drift chamber determine?


  Thee mass of the isotope.
• What does the size of the current produced determine?


  The abundance of each isotope.
• Why is the interior of the mass spectrometer a vacuum?


  To prevent the ions from collide atoms in the air.
• What is the m/z ratio?


  Ratio o the mass of each ion to its charge.
• What can the mass spectrometer measure of an isotope?

  The m/z rate and an abundance.
• How do you calculate RAM?

  Sum of isotopic mass x percentage abundance of all isotopes divide by 100.
• What is the ratio of the Cl isotopes?

  3:1
• What is the ratio of the Br isotopes?

  1:1
• How do you measure the Mr of a molecule through a mass spectrometer?

  The tallest m/z peak to the right as it is the complete molecule and is equal to the Mr. There will be other peaks due to other fragments.
• What are the uses of mass spectrometers?

  1. Planetary space probes can identify in other planets.
  2. Drug testing in sport
  3. Quality control in pharmaceutical industry and to identify molecules from samples.
  4. Radioactive dating.