Fig. 1. Overview of a GC-MS chromatogram from an Arabidopsis
leaf extract (here, ecotype Cvi-0). (a) total ion current chromatogram,
showing annotation of typical peaks (in red). The observed mass spectrum
at 15.05 min is shown in (b), with characteristic ions of
6-phosphogluconate 3TMS annotated in red. Note the contribution of ion
m/z = 387.14254 Da (fragment
C13H32O7PSi2+).
Note that a close, but easily distinguishable mass (387.32912 Da,
fragment
C22H47O3Si+)
can be observed at 15.25 min, from arachidic acid 1TMS; nominal mass
analysis would have generated the same apparent mass at 387 (or 388) Da.