lecture 11: mass spec Flashcards
(8 cards)
What is a high resolution mass spectrometry?
provides the highest precision in measuring the mass-to-charge ratio of molecules, used to identify compounds.
What is the base peak?
the tallest peak, corresponding to the most common fragment
What is the molecular ion or parent peak?
M+, corresponds to unfragmented radical cations (gives molecular mass)
What is the difference between nominal mass, atomic mass and molecular mass?
atomic: weighted average of the masses of the isotopes of an element
molecular: sum of the average masses of its atoms
nominal: integer mass of a molecule or ion.
What is fragmentation?
dissociation of bonds in cation radical. Positive charge remains often with the fragment, which will form the more stable carbocation
What does a M+ - 15 mean
CH3+
What does a M+ -29 mean?
CH3CH2+
What does M+ -43 mean?
CH3CH2CH2+
