Mass Spectrometry

Question 1

an analytical chemistry technique that helps identify the amount and type of chemicals present in a sample by measuring the mass-to-charge ratio and abundance of gas-phase ions.

Answer 1

Mass Spectrometry (MS)

Question 2

2 division of Mass Spectrometry

Answer 2

• Atomic or Elemental Mass Spectrometry
• Molecular Spectrometry

Question 3

• Can determine nearly all the elements in the periodic table
• Detection limits are often several orders of magnitude better than optical methods

Answer 3

Atomic/ Elemental MS

Question 4

Can provide information about the structures of inorganic, organic, and biological molecules

Answer 4

Molecular MS

Question 5

Basic Principles of MS

Answer 5

• Molecules are bombarded with a beam of energetic electrons.
• Each kind of ion has a particular ratio of mass to charge
• The ions pass through magnetic and electric fields
• A mass spectrum is a plot of relative abundance against the ratio of mass/charge (m/e).

Question 6

Instrumentation and Steps of MS

Answer 6

• Sample Inlet
• Ionization
• Acceleration
• Deflection
• Detection

Question 7

A sample stored in the large reservoir from which molecules reach the ionization chamber at low pressure

Answer 7

Sample Inlet

Question 8

Atoms are ionized by knocking one or more electrons off to give positive ions by bombardment with a stream of electrons.

Answer 8

Ionization

Question 9

• Ions are accelerated so that they all have the same kinetic energy

Answer 9

Acceleration

Question 10

Ions are deflected by a magnetic field due to differences in their masses

Answer 10

Deflection

Question 11

The beam of ions passing through the mass analyzer is detected by a detector on the basis of the m/e ratio.

Answer 11

Detection