Electrospray

Subdecks (1)

Cards (7)

  • Ionisation
    Sample is dissolved in a polar volatile solvent and is put through a hypodermic needle attached to a positive terminal with a high voltage
    As particles leave the needle they are ionised and gain a proton
  • Acceleration
    Particles are accelerated through a electric field consisting of 2 negatively charged plates, and therefore increase the kinetic energy of the ions
    Ions will accelerate at different speeds depending on their mass to charge ratio lower mz = greater acceleration higher mz = lower acceleration
  • Ion drift
    ions enter a region with no electric field, so they drift at different speeds depending on their mass to charge ratio
  • Detection
    Ions with a lower mz ratio reach the detector in less time than those with a higher mz, as they reach the detector electrons from the negative plate flow to the positive ions and a current is induced
    Time taken to move down the spectrometer is used to determine the mass of isotope
    Size of current induced is used to measure the abundance of isotope
  • Equation for electrospray ionisation:
    X+ H+ = XH+