TABLE 2

Identities of the various forms of ECG (Fig. 5B)

All of the ions are associated with the same ECG molecule but are detected by the mass spectrometer as different isotopes or adducts.

NumberIon (m/z)Molecular FormulaΔ (ppm)Tentative Identification
1443.0869 [M-H]C22H17O10+ 0.913C isotope peak of ECG
2504.0890 [M+ACN+Na-2H]C24H19NO10Na+ 2.7Acetonitrile-sodium adduct of ECG
3477.0597 [M+Cl]C22H18O10Cl+ 0.8Chloride adduct of ECG
4441.0832 [M-H]C22H17O10+ 1.1Deprotonated molecular ion of ECG
5442.0864 [M-H]C22H17O10+ 1.813C isotope peak ECG
6487.0886 [M+FA-H]C23H19O12+ 1.0Formic acid adduct of ECG
  • ACN, acetonitrile; FA, formic acid.