Mass Spectrometry (General)

Question 1

MS (Scheme)

Answer 1

Sample -> [ Inlet System -> Ion Source -> Mass Analyser -> Detector ]vacuum sys -> Signal processing -> readout

Question 2

MS (Sample Introduction)

Answer 2

Gases/Volatiles - Leak Valve
Liquids - Hypodermic syringe through a septum
Solids - Temperature programming lance and air lock
Others - HPLC, GC

Question 3

EI (Defintion and Scheme)

Answer 3

Electron Impact Ionisation

Electrons released from hot filament and electrons excited to 70eV.

Electrons pass through ionisation chamber and ionise vapour via collision.

Energy is large enough to multiply ionise and fragment molecule present

Question 4

MS (Magnetic Deflection)

Answer 4

Ion beam has a current which is affected by magnetic fields

Question 5

MS (Transducers)

Answer 5

Electron multiplier is the most common for MS

Question 6

MS (Detectors)

Answer 6

Channeltron particle detector

Question 7

MS (Analysis)

Answer 7

Isotopic abundances, Cl(35), Cl(37), Br(81), Br(79)

Question 8

HR-MS (Definition)

Answer 8

Double/Triple focussing with additional sectors. Allows for accurate measurements of masses and determines molecular formula

Question 9

Mass Spectrometry (Information)

Answer 9

Nominal molecular mass samples, observe fragmentation (patterns)

Confirms presence of isotopes, molecular formula and accurate mass

Question 10

Mass Spectrometry (Applications)

Answer 10

• Identification of banned substances
• Forensic Application
• Medical Application (Heavy metal toxicity)