Mass Spectrometry Principles Revision Lecture

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What ionization method is suitable for many non-polar compounds?

Electrospray ionization (ESI)

Protonation

Atmospheric pressure photoionization (APPI) (correct)

Photoionization

Which ionization method produces radical ions and protonated/deprotonated species?

Electrospray ionization (ESI)

Protonation

Deprotonation

Photoionization (correct)

What does the spacing between isotopologues determine in mass spectrometry?

Molecular weight

Charge state (correct)

Resolving power

Neutral molecule mass

Which parameter tells us about the charge state in mass spectrometry?

Isotopologue spacing Signup and view all the answers

In electrospray ionization (ESI), what is measured on the mass spectrometer?

$M + nH+$ Signup and view all the answers

What should the resolving power have to be in order to resolve isotopologues in mass spectrometry?

High Signup and view all the answers

Which course should students search for if they are looking for past papers from the year 2021?

CH3G5 Signup and view all the answers

Which topic was included in the older course but is not part of CH3F2 from 2019-2020 onwards?

Interpretation of EI mass spectra Signup and view all the answers

In which book can students find information on Mass Spectrometry?

Mass Spectrometry: Principles and Applications by Edmond de Hoffmann and Vincent Stroobant Signup and view all the answers

Which author did not write a book on Mass Spectrometry?

Laura Brown Signup and view all the answers

Where can students find past papers for the year 2020-2021?

Moodle platform Signup and view all the answers

What is the correct formula for the neutral form of naphthalene?

C10H8 Signup and view all the answers

In positive-ion mode for naphthalene by APPI, what is the correct representation for the singly-charged species?

C10H8 + H Signup and view all the answers

What is the charge on an electron?

1.60 x 10^-19 C Signup and view all the answers

What is wrong with the calculation that was performed for the neutral form of C10H8?

Used average masses instead of monoisotopic masses Signup and view all the answers

Which unit should be used for reporting masses instead of 'amu'?

Da Signup and view all the answers

What number of significant figures should have been used in the calculation?

~5 Signup and view all the answers

Why is MALDI ionization well-suited for polymer analysis?

It avoids the formation of multiply-charged ions. Signup and view all the answers

In MALDI-TOF, what is the role of the TOF mass analyzer?

It provides resolving power for the experiments. Signup and view all the answers

How is the n value calculated in the given equations?

n = (b - 1.007) / (a - b) Signup and view all the answers

What experimental advantages does TOF offer in MALDI-TOF analysis?

High speed of data acquisition Signup and view all the answers

How does the combination of MALDI and TOF overcome data analysis complexities in polymer analysis?

By avoiding overlaps of polymer distributions. Signup and view all the answers

What is the purpose of choosing an organic matrix in MALDI ionization technique?

To minimize the fragmentation of the analyte Signup and view all the answers

In MALDI, what is the typical ratio of matrix to analyte in the solution prepared for deposition?

1000:1 Signup and view all the answers

What is the role of the UV laser in MALDI ionization?

To facilitate ionization of the analyte molecules Signup and view all the answers

Which ionization mode occurs when the analyte is protonated in MALDI?

Positive-ion mode Signup and view all the answers

What is a common observation in APPI mechanisms according to the text?

Aliphatic compounds show loss of CO2 and HCOOH in APPI Signup and view all the answers

What nomenclature was proposed by Roepstorff and Fohlman regarding sequence ions in mass spectra of peptides?

Roepstorff cleavage nomenclature Signup and view all the answers