Quality structural annotation for the metabolites of chlorogenic acid in rat

Full collision energy ramp‐MS2 spectral features of natural esters: Salvianolic acid A as a case

“…After the acquisition of the HR‐MS/MS spectrum, SA is subjected to FCER‐MS 2 spectral measurement by tightly following the workflow described previously 2 . As shown in Figure 2, the FCER‐MS 2 spectrum consists of the breakdown graphs of all MS 2 spectral signals, not limited to those featured ions.…”

“…We then study the relationships between OCEs and the structural properties. When the FCER‐MS 2 spectra characteristics of chlorogenic acid and its isomers are combined, 2 we observe that the OCE of z − ( m/z 173.0455, −40.38 eV) is always greater than that of y − ( m/z 191.0556, −28.66 eV), and the OCE values usually follow the ranking pattern as a − ( m/z 135.0446, −48.66 eV) > b − ( m/z 161.0224, −33.92 eV) > c − ( m/z 179.0344, −26.55 eV), suggesting negative correlations with HR‐ m/z values. Although either c − or z − is produced by the dissociation of the O–C bond (length: 1.45 Å), the ranking position is independent of the ranking style of bond lengths as the C–C bond (length: 1.48 Å) > O–C bond (length: 1.45 Å) > C–O bond (length: 1.35 Å) obtained using Gaussian 09W software (Gaussian, Inc., Wallingford, CT, USA).…”

“…1 Here, we evaluate whether the MS/MS patterns of esters are comparable with those of peptides. In particular, full collision energy ramp-MS 2 (FCER-MS 2 ) spectrum 2 implies that all information on fragment ions, such as high-resolution m/z (HR-m/z), optimal collision energy (OCE), and maximal relative ion intensity (RII max ), is constructed for a representative natural ester, namely salvianolic acid A (SA), which is a primary contributor to the therapeutic spectrum of a well-known herbal medicine, namely Salviae Miltiorrhizae Radix et Rhizoma (Chinese name: Danshen), 3 to illustrate the empirical properties.…”

“…LC-MS/MS data set of those ester-enriched herbal medicines, such as Peucedani Radix, 4 Polagalae Radix, 5 Cistanches Herba, 6 Lonicerae japonicae Flos, 7 Inulae Flos, 7 and Aconiti Radix, 8 179.0340, 173.0445, 161.0232, and 135.0438, are observed as the primary fragment ion species for chlorogenic acid as well as its isomers, namely neochlorogenic acid and cryptochlorogenic acid. 2,7 After referring to the ion nomenclature fashion of peptides, 9 we propose the nomenclature rule here for those featured ester ions. The ester group is defined as the scaffold of the entire structure, and the carbonyl carbon is placed on the left.…”

“…The unique mass differences of 25.98 and 18.01 Da definitely exist. Moreover, some other fragment ion species, such as m/z 203.0349, 185.0257, 159.0449, 135.0452, and 109.0293, the generation of which is independent of the ester group, also occur as the fragment ion species (Figure1B).After the acquisition of the HR-MS/MS spectrum, SA is subjected to FCER-MS 2 spectral measurement by tightly following the workflow described previously 2. As shown in Figure2, the FCER-MS 2 spectrum consists of the breakdown graphs of all MS 2 spectral signals, not limited to those featured ions.…”