3.1.1 Atomic Structure

Question 1

What is the primary use of time of flight analysis? (3)

Answer 1

Environmental, Pharmaceutical, Forensic analysis

Question 2

What is the advantage of conducting time of flight analysis in a vacuum? (1)

Answer 2

No interference from other particles

Question 3

What are the main stages of time of flight analysis & Acronym? (6)

Answer 3

VIAIDA
* Vacuum
* Ionisation
* Acceleration
* Ion drift
* Detection, Analysis
* Analysis

Question 4

Electrospray ionisation process (4)

Answer 4

• Sample dissolved in highly volatile polar solvent
• Injected through need at high voltage
• Each particle gains a proton (H+) to for 1+ ions
• X(g) + H+ -> XH+(g)

Question 5

How and why are ions accelerated? (2)

Answer 5

Accelerated by electric field to constant KE
Same KE - different masses of ions travel at different speeds

Question 6

Kinetic energy equation (1)

Answer 6

KE = m x v^2

Question 7

Electron impact ionisation process (4)

Answer 7

• High energy e- fired from e- gun
• Knocks off e- from each particle
• Forms 1+ ions
• X(g) → X+(g) + e-

Question 8

What is the role of acceleration in time of flight analysis? (1)

Answer 8

To increase the kinetic energy of ions for their drift towards detection