Flashcards in Mass spectrometry Deck (10):
this technique tells us
molar mass of a compound
describe how fragmentation occurs.
in the ionisation chamber, high energy electrons dislodge one electron from the molecule forming the molecular ion.
M + e- -> [M]+ + 2e-
Molecular ion is unstable because only one electron is unpaired, so it breaks into fragment ions, one of which is charged.
name of the graph?
define: molecular ion
formed when the entire molecule loses an electron
describe m/z ratio of the molecular ion
charge is one, mass is its molar mass, hence m/z ratio is the molar mass
define: fragment ions
forms when molecular ion splits due to its instaility
define: base peak
produced by most abundant ion - relative intensity set to 100%, other relative intensities are compared to it
what isotopes do we need to watch out for
79Br and 81Br
35Cl and 37Cl
CHO isotopes arent anywhere near as abundant.
what happens to 79Br and 81Br, 35Cl and 37Cl isotopes
have different molar masses os form peaks.