The collision-induced dissociation (CID) spectrum of m/z 130, which corresponds to the protonated molecular ion
of the racemic PA mixture, is shown in Fig.
In addition the design of the electrospray ion source can permit a molecular ion
to undergo a process known as collisionally induced decomposition.
The EI-MS of 1 displayed a molecular ion
peak at m/z 545 indicating the presence of odd number of nitrogen atom in 1.
For n-butyl-SA the major product ions from the M+1 molecular ion
were obtained by the loss of 74 and 130 Da.
The sample readily fragments after EI, while CI often produces only a single, protonated, molecular ion
Thus it showed the presence of the molecular ion
peak at 291 and a number of fragments agree with the proposed structure (Scheme-1).
This spectrum was acquired by transmitting the protonated molecular ion
via [Q.sub.1] and scanning the second resolving quadrupole, [Q.sup.3], for products resulting from fragmentation in the collision cell.
The HR-EI-MS displayed molecular ion
peak at m/z344.0873 corresponding to the molecular formula C18H16O7 with eleven double bond equivalence (DBE).
Both of these spectra were acquired by [Q.sub.1] transmission of the protonated molecular ion
, m/z 231, and scanning the second resolving quadrupole ([Q.sub.3]) for products resulting from fragmentation in the collision cell.
Conversely, for homologous series of compounds IR spectra can be very similar, while mass spectra can provide definitive identification from molecular ion
The signals of the molecular ion
(M) and of its [sup.13]C-containing fragments (F), chosen for M/M+1 or F/F+1 peak selective monitoring, show low intensity, and some other fragments of identical mass may produce interfering signals.