Mass Spectrometry

Question 1

What are the three stages of mass spectrometry?

Answer 1

Ionisation, mass to charge analyser and detection.

Question 2

Describe the steps in mass spectrometry?

Answer 2

The ionisation source could be ESI or MALDI, the mass to charge analyser separates ions on the bases of mass to charge ratios they can be quadrupole or time of flight analysers, the detector amplifies the current and records it as a mass spectrum.

Question 3

What information can the mass spectrum provide?

Answer 3

Number of components, mass of components, relative abundance of the components.

Question 4

What do each ionisation source give the results in?

Answer 4

MALDI: positive or negative ion mode extend have to plus or minus a proton mass.
ESI: for small peptides below 1 kDa you have to minus the mass of a proton. For large you use M+(nx1)/ n

Question 5

What is tandem mass spectrometry?

Answer 5

Provides structural information using multianalyser:
Either quadrupole-quadrupole, TOF-TOF, quadrupole-TOF. Has an argon collision cell to fraction the peptide sample to give individual residue peaks.

Question 6

What is mass spectrometry for?

Answer 6

To analyse protein samples structure.