Revise 3

Question 1

What is the size of current in mass spec proportional to?

Answer 1

Abundance of species

Question 2

Why does mass spec need to be under a vacuum?

Answer 2

Air particles may ionise & register on detector

Question 3

What would the m/z of 24Mg2+(doubly-charged ion) with a 2+ charge be?

Answer 3

12

Question 4

Copper has two isotopes 63-Cu and 65-Cu. The relative atomic mass of copper is 63.55. Calculate the percentage abundances of these two isotopes.

Answer 4

63.55 = y x 63 + (1-y )x 65
63.55 = 63y + 65 - 65y
63.55 = 65 - 2y
2y = 1.45
y = 0.725
%abundance 63-Cu =72.5% %abundance 65-Cu = 27.5%

Question 5

What should you give when asked to give the species for a peak in a mass spectrum?

Answer 5

Charge and mass number e.g. 24Mg+