Which Statements Are True for the Various Ion Selection Techniques

question 3

Multiple Choice

Which statements are true for the various ion selection techniques?
I Time-of-flight MS - Ions expelled from the source all have the same kinetic energy.For ions of different masses but equivalent kinetic energies,the lighter ions travel faster than heavier ions,separating the ions.
II Quadrupole MS - A constant voltage and a radio-frequency oscillating voltage is applied to the four metal rods.The electric field deflects ions in complex trajectories as the ions migrate from source to detector,allowing only one particular m/z to reach the detector.
III Three-dimensional quadrupole ion-trap MS - A constant-frequency radio-frequency voltage is applied to the central ring electrode causes ions to circulate in stable,three-dimensional orbits in the cavity,with the lowest m/z in the outermost orbits.Increasing the amplitude of the radio-frequency voltage destabilizes m/z ion orbits one value at a time.
IV Magnetic sector MS - Ions are accelerated into the magnetic sector with equivalent kinetic energies.Ions are selected by passing through a magnetic field;lighter ions are deflected the most and the heavier ions are deflected the least.The magnetic field is varied to select individual m/z.

• A)I,II,and IV
• B)I,II,III,and IV
• C)II,III,and IV
• D)II and IV
• E)III and IV