6.7.1 Mass Spectrometry

• Mass spectrometry is an analytical technique that measures the relative mass and abundance of different ions
• What does the height of a peak in a mass spectrum represent?

  Relative abundance
• The base peak in a mass spectrum is the most abundant ion.
• Match the feature of a mass spectrum with its description:

  Base Peak ↔️ Most abundant ion

  Molecular Ion Peak ↔️ Represents the original molecule

  Fragment Peaks ↔️ Pieces of the original molecule
• Stages in the principles of mass spectrometry

  1️⃣ Ionization

  2️⃣ Acceleration

  3️⃣ Deflection

  4️⃣ Detection
• Fragmentation patterns in mass spectra are unique fragment ions produced by the breaking of bonds
• What group is highlighted by the loss of $H_{2}O$ in fragmentation patterns?


  $–OH$ group
• The mass analyzer in a mass spectrometer separates ions based on their $m / z$ ratio.
• Match the component of a mass spectrometer with its function:

  Ion Source ↔️ Creates charged ions

  Mass Analyzer ↔️ Separates ions by $m / z$

  Detector ↔️ Measures ion abundance
• When analyzing a mass spectrum to identify an unknown compound, you should first examine the molecular ion peak
• What does the $m / z$ of the molecular ion peak indicate?


  Molecular weight