WM4: Mass Spectrometry

Question 1

What 2 functions can mass spectroscopy tell us?

Answer 1

1. Mass of a molecule
2. Isotopic abundance of elements

Question 2

What are found on the x and y axis of the mass spectra?

Answer 2

x axis = m/z
y = intensity or abundance

Question 3

what does m/z mean?

Answer 3

mass per charge, this helps us not record ions with a charge greater than +1

Question 4

What peak do we use to find the mass of molecule?

Answer 4

Molecular ion peak (M+) peak, remember all peaks are formed from positive ions

Question 5

What is the reason for the other peaks?

Answer 5

The molecule breaks apart into different parts in what we call the fragmentation pattern

Question 6

What is the cause of the M+1 peak?

Answer 6

This is caused by the presence of the Carbon-13 isotope. There is a 1.1% change of a carbon being a C-13 isotope.

Question 7

What is an isotope?

Answer 7

Elements with the same number of protons and different number of neutrons

Question 8

What would be the M+ peak for 2-ethoxybutane?

Answer 8

M+ = 102