The early eluting peaks at ~3.5 min gave a protonated molecular ion
at m/z 148, which corresponded to glutamic acid and cochromatographed with pure L-glutamic acid.
The only difference was observed in mass spectral data of 2, as HR-EI-MS displayed molecular ion
at m/z 517.4462 corresponding to the molecular formula C 33 H 59 NO 3 .
The molecular ions
[[M + H].sup.+] and [[M + [NH.sub.4]].sup.+] were observed for all dicarboxylic acids that were evaluated, including MMA, SA, malonic, 2-hydroxyglutaric, adipic, ethylmalonic (EMA), dimethylmalonic (DiMMA), suberic, sebacic, and dodecanedioic acids.
Thus it showed the presence of the molecular ion
peak at 339 and a number of fragments agree with the proposed structure (Scheme-1).
The HR-EI-MS displayed molecular ion
at m/z 328.0938 corresponding to the molecular formula C18H16O6 with one oxygen atomless than that of 1.
Because the molecular ions
of N-alkylated carbamic acids are stable during GC-MS analysis, the M/M+1 and F/F+1 peak ratios can be easily measured by this technique.
This spectrum was acquired by transmitting the protonated molecular ion
via [Q.sub.1] and scanning the second resolving quadrupole ([Q.sub.3]) for products resulting from fragmentation in the collision cell.
The M8 metabolite is not shown because its molecular ion
was not monitored.
1 shows the parent ion spectrum of the molecular ion
(precursor ion) for pure octanoylcarnitine and [[sup.2][H.sub.3]]octanoylcarnitine.