ToF mass spectrometry

• What does TOF mass spectrometry provide information about?

  Relative isotope mass and abundance
• How can relative atomic mass (Ar) be calculated using TOF mass spectrometry?

  By analyzing relative isotope mass and abundance
• What is one use of TOF mass spectrometry?

  To identify elements
• What does TOF mass spectrometry determine about molecules?

  Relative molecular mass (Mr)
• What information can be deduced about molecules using TOF mass spectrometry?

  Information about the structure of molecules
• What happens to samples in TOF mass spectrometry?

  Samples are converted to positive ions
• What determines the speed of ions in TOF mass spectrometry?

  The mass-to-charge ratio of ions
• What is the purpose of the vacuum in TOF mass spectrometry?

  To prevent ions from colliding with air molecules
• What occurs during the acceleration phase in TOF mass spectrometry?

  Positive ions are attracted to a negatively charged plate
• How do lighter ions behave compared to heavier ions in TOF mass spectrometry?

  Lighter ions arrive at the detector quicker
• What happens to positive ions when they reach the detector?

  They gain an electron, causing a current
• What is generated from the signal passed to a computer in TOF mass spectrometry?

  A mass spectrum
• What is the process of electrospray ionisation?

  Sample is dissolved in a volatile solution and forced through a fine hollow needle connected to a positive terminal at high voltage supply. Tiny, positively charged droplets are produced. Solvent evaporates and droplets get smaller until they contain a single positively charged ion.
• What is the equation for electrospray ionisation?

  X(g) + H+ -> XH+(g) + e-
• Electron Impact Ionisation


  A process where a high-energy electron beam collides with a gas molecule, causing ionisation and production of ions. the high energy electrons are fired from an electron gun.
• What is an electron gun?

  Hot wire filament with a current running through it that emits A beam of high energy electrons
• What is the equation for electron impact ionisation?

  X(g) + e- -> X+(g) + 2e-
• What is ion drift?

  When ions pass through a hole in the negative plate, forming a bean and travel along the flight tube.