Mass Spectrometry

Question 1

What can fragmentation do to a molecular ion?

Answer 1

> Split it into a positive ion (⁺) and a radical () at any point within the molecule
Each separate positive ion (⁺) and radical () has their own peaks

Question 2

What are the axis on a mass spectrometer?

Answer 2

y axis: Abundance

x axis: Mass/charge ratio (since charge is usually +1. this is just relative mass)

Question 3

What is the molecular ion peak?

Answer 3

> The peak representing the unfragmented molecular ion

Question 4

What is the base peak?

Answer 4

> The tallest peak in the spectrum

> The most stable isotope cation

Question 5

What is the symbol for a molecular ion?

Answer 5

M⁺*

Question 6

What are high-resolution mass spectrometers for?

Answer 6

> Measuring the precise mass : charge ratio of any molecule, of which such value can be matched to experimental integral values for molecular formulas

Question 7

What is the M +1 peak?

Answer 7

A peak one unit right from the molecular ion peak showing abundance of molecules with C-13, Cl-35 or Br-79 isotopes

Question 8

What is the M +2 peak?

Answer 8

A peak 2 units from the molecular ion peak showing abundance of molecules with Cl-37 or Br-81 isotopes