Mass Spectroscopy

Question 1

What is mass spec ?

Answer 1

Manipulates ions in a vacuum to measure their mass-to-charge ratio (m/z)

Question 2

What are the ionisation techniques in mass spec ?

Answer 2

1. Electron impact
2. Electro spray ionisation
3. MALDI

Question 3

Describe electron impact

Answer 3

High energy electrons knock electrons off molecules
Causes fragmentation

Question 4

Describe MALDI

Answer 4

Uses laser to desorb and ionise large biomoleucles

Question 5

Describe types of mass analysers

Answer 5

1. Quadrupole- only ions with a specific m/z are able to pass through it
2. Ion trap
3. TOF- measures the time it takes for ions to reach the detector. Lighter ions arrive faster.

Question 6

What is the tallest peak in mass spec ?

Answer 6

The base peak, which is the most abundant ion

Question 7

What is the molecular ion (M+) ?

Answer 7

The peak corresponding to the intact (unfragmented) ion in the sample.
Often has the highest m/z value
Can be absent