Analytical Chemistry

(Chris Devlin) #1
Figure 9.52
(a) Main processes in tandem mass
spectrometry (MS/MS). CID stands
for collision-induced dissociation,
as occurs when an inert gas is
present in the collision cell. CAR
stands for collision-activated
reaction, occurring when a reative
gas is present in the collision cell.

Figure 9.52
(b) Top: electron impact spectrum of p-t-butylphenol. Spectrum
(a): fragments of the precursor ion m/z 135. This spectrum shows that
the ion of m/z 107 results from a loss of 28 after the loss of a methyl by
the molecular ion. Spectrum
(b) proves that the oxygen atom is not lost during this fragmentation: the
loss of 28 is thus a loss of C 2 H 4 , not of CO.

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