spectroscopy

• Fingerprint region

  An area of an infrared spectrum below 1500 cm-1 that gives a characteristic pattern for different compounds
• Fragment ions

  Ions formed from the breakdown of the molecular ion in a mass spectrometer
• Fragmentation


  The process in mass spectrometry that causes a positive ion to split into smaller pieces, one of which is a positive fragment ion
• The higher an object’s speed, the higher its kinetic energy
• The greater an object’s mass, the higher its kinetic energy
• To use a charged plate to give atoms kinetic energy, we first need to ionise them
• X-axis on the mass spectrum is m/z ratio (which can represent mass)
• Y-axis on the mass spectrum is relative abundance or intensity
• On the mass spectrum we assume they are 1+ ions
• Percentage abundance:

  1. Find the total number of ions
  2. Divide the relative intensity of each isotope by the total number of ions
  3. Multiply by 100
• if y-axis shows relative intensity you must calculate percentage abundance
• We can then use percentage abundance to find relative atomic mass
• In mass spectrometry ion with the smallest mass / charge ratio travels the fastest
• The most abundant ion generates the largest electrical current at the detector