Table 1.
List of characteristic oxonium ions originating from the fragmentation of the glycan of glycopeptides and observed in their CID spectra.
| Oxonium Ion (m/z) | Description | |
|---|---|---|
| 1 | 127.06 | Hex – 2H2O |
| 2 | 138.05 | HexNAc – several functional groups |
| 3 | 163.06 | Hex |
| 4 | 168.09 | HexNAc – 2H2O |
| 5 | 186.09 | HexNAc – H2O |
| 6 | 204.09 | HexNAc |
| 7 | 274.09 | NeuAc – H2O |
| 8 | 292.08 | NeuAc |
| 9 | 366.14 | HexHexNAc |
| 10 | 657.23 | NeuAcHexHexNAc |
Abbreviations: HexNAc, N-acetylhexoseamine e.g. N-acetylglucosamine (GlcNAc) or N-acetylgalactosamine (GalNAc); Hex, any hexose e.g. mannose (Man), or galactose (Gal); NeuAc, N-acetylneuraminic acid or sialic acid; −H2O, loss of water.