4.5.2 Mass spectrometry (MS)

• What is mass spectrometry (MS) used to identify and determine?

  Molecules and molecular mass
• Arrange the steps of mass spectrometry in the correct order:

  1️⃣ Ionization

  2️⃣ Acceleration

  3️⃣ Deflection

  4️⃣ Detection
• The detection step in mass spectrometry measures the abundance of ions at each m/z value to create a mass spectrum.


  True
• What type of fragmentation occurs in Electrospray Ionization (ESI)?

  Minimal fragmentation
• The mass spectrometer produces a mass spectrum
• Electrospray Ionization (ESI) causes minimal fragmentation of molecules.


  True
• A mass spectrometer produces a spectrum by measuring the abundance of ions at each m/z value.
• Steps in interpreting mass spectrometry (MS) data

  1️⃣ Identify the molecular ion peak

  2️⃣ Analyze fragment ions

  3️⃣ Determine molecular mass

  4️⃣ Deduce structural information
• The molecular ion peak's m/z value indicates the molecule's molecular mass.
• Match the MS data feature with its description:

  Molecular Ion Peak ↔️ Highest mass peak

  Fragment Ions ↔️ Series of lower mass peaks
• MS is used to determine the molecular mass of a compound by analyzing the molecular ion peak.
• Match the MS concept with its explanation:

  m/z ↔️ Ratio of mass to charge

  Deflection ↔️ Determined by m/z

  Molecular Ion Peak ↔️ Represents parent ion
• What are two applications of MS in organic chemistry?

  Determining molecular mass and identifying unknown substances
• The first step in mass spectrometry is ionization
• How are ions deflected in the magnetic field of a mass spectrometer?

  By their mass-to-charge ratio
• Electron Impact (EI) is a gas-phase ionization technique that uses high-energy electrons
• Match the ionization technique with its key characteristic:

  Electron Impact (EI) ↔️ High fragmentation

  Electrospray Ionization (ESI) ↔️ Minimal fragmentation
• What type of ionization is used in Electron Impact (EI)?

  Gas phase
• Electron Impact (EI) is a gas-phase ionization technique where molecules are bombarded with high-energy electrons to produce a fragmentation pattern.
• Match the MS characteristic with its explanation:

  m/z ↔️ Ratio of ion's mass to charge

  Deflection ↔️ Lighter ions deflect more

  Importance ↔️ Identifies structure and mass
• The m/z value determines how much an ion is deflected in the magnetic field of the mass spectrometer.

  True
• What does the molecular ion peak represent in MS data?

  Parent ion (M+)
• Fragment ions provide insights into the molecule's structure by revealing specific structural components.


  True
• What is one application of MS in organic chemistry?

  Determining molecular mass
• Fragmentation patterns in MS can reveal the arrangement of functional groups in a molecule.

  True
• The molecular ion peak's m/z value indicates the molecule's molecular mass.