17.1 - Mass Spectroscopy

Question 1

What can mass spectra be used to determine?

Answer 1

• The molecular mass of an organic compound.

- Can be used to gain further information about its structure.

Question 2

What is the molecular ion?

Answer 2

The molecular ion is the positive ion formed when a molecule loses an electron.

Question 3

Why is there a small peak next to the molecular ion peak?

Answer 3

It is the M + 1 peak.

It is an isotope of the molecular ion.

Question 4

What is fragmentation?

Answer 4

Molecular ions can break down into smaller pieces called fragments.

Question 5

What does the simplest fragmentation break a molecular ion into?

Answer 5

A positive ion (detected by mass spectrometer) and a free radical.

Question 6

How can mass spectrum be used to identify different compounds with same molecular mass?

Answer 6

The fragment ions found in the spectrum may be different.

Question 7

What would a peak be at m/z = 15?

Answer 7

CH3+

Question 8

Where is mass spectrometry used?

Answer 8

Drug testing (doping in sports)
Food contamination detection