The MS spectra of the analytes and these of standards there was a fantastic match of your RT values and exact mz ratios of your [MH] and [MH] ions (Tables and) as well as of your MS spectra of the [MH] ions (Tables and).Frontiers in Plant Science www.frontiersin.orgNovember Volume ArticleSisTerraza et al.Coumarins in FeDeficient Arabidopsis PlantsFIGURE Chromatographic separation of a selection of phenolictype compounds created in response to Fe deficiency by Arabidopsis thaliana roots.Typical fluorescence (at exc and em nm) and absorbance (at nm) chromatograms for root and growth media extracts from plants grown as described in Fourcroy et al. plants had been pregrown for days within the presence of Fe (III)EDTA at pH then grown for days in a medium with (Fe) or Fe (III)EDTA (Fe) (the pH was not readjusted to together with the final pH getting c..in all pots).Chromatograms have been obtained using Elution program .The encircled numbers above every peak correspond for the phenolic compounds listed in Table .RU, relative units, AU, absorbance units, and RT, retention time.4 more compounds were first confirmed to become hexosidetype compounds in the RT, exact mz values and MS spectra with the [MH] ions.The RT values of these compounds (.min) have been close to these of recognized coumarin glucosides (.and .min for scopolin and fraxin, respectively), and reduced than these of coumarin aglycones (.min for fraxetin, scopoletin, isofraxidin and fraxinol), phenylpropanoids (e.g .and .min for ferulic acid and sinapyl aldehyde), and glycoside and aglycone types of other phenolics (e.g min for flavonoids, stilbenes and lignans) (Supplementary Figures S and S).For that reason, the RTs indicate that compounds are likely to be polar (i.e hexoside) forms of coumarins andor phenylpropanoids.Additionally, in the MS(TOF) spectra, ions (positivenegative) at mz .and .for , , , and , respectively, were consistent with all the loss of a hexosyl moiety (.Da) from their corresponding [MH] [MH] ions (see mz values in Table).This was confirmed employing the low resolution MS spectra obtained using the ion trap important fragment ions (relative intensity at mz , , and in the MS spectra of , respectively; Table) corresponded to the [MH] ions (mz , , and for , , , and , respectively) immediately after a mass loss of Da.The identical mass loss was also observed within the MS spectra of authenticated requirements in the coumarin glucosides scopolin and fraxin described above, with main ions at mz (scopolin) and (fraxin), corresponding with all the mz of their aglycones, scopoletin andfraxetin, respectively (Table).The rest of ions inside the MS spectra of compounds , scopolin and fraxin showed considerably reduced relative intensities , indicating the hexosyl loss is favored.The aglycon moieties of compounds had been identified taking advantage of possessing the dehexosylated ions in the MS(TOF) spectra and also carrying out low resolution MS experiments around the ion trap.Initial, in the good and unfavorable MS(TOF) spectra, the mz values for dehexosylated ions (see above) of , , , and have been assigned towards the elemental formulae C H O , C H O , C H O and C H O , respectively (with absolute errors ppm).Two of those elemental formulae, C H O and C H O , had been constant with coniferyl and sinapyl aldehydes, involved in coumarin AUT1 Solubility synthesis (Kai et al) (Table), whereas the other two, C H O and C H O , have been consistent with two coumarins currently identified in the samples (compounds PubMed ID:http://www.ncbi.nlm.nih.gov/pubmed/21541725 and , respectively) (Table).Ultimately, compounds have been confirmed.