Table I.
Major molecular ions of oligosaccharides observed in the negative-ion ESI mass spectra
|
m/z |
||||
|---|---|---|---|---|
| No. | Structure | Molecular ion | Calculated | Observed |
| 2a | ΔUA2S-GlcNS | [M-H]− | 496.0 | 495.7a |
| 2b | ΔUA2S-GlcNS6S | [M-H]− | 576.0 | 575.6a |
| 4a | ΔUA2S-GlcNS6S-IdoA2S-GlcNS | [M-2H]2− | 536.0 | 535.8a |
| 4b | ΔUA2S-GlcNS6S-GlcA-GlcNS6S | [M-2H]2− | 536.0 | 535.8a |
| 4c | ΔUA2S-GlcNS6S-IdoA2S-GlcNS6S | [M-2H]2− | 576.0 | 575.7a |
| 5 | ΔUA2S-GlcNS6S-IdoA-GlcNAc6S-GlcA | [M-2H]2− | 605.0 | 604.8a |
| 6a | ΔUA2S-GlcNS6S-IdoA2S-GlcNAc-GlcA-GlcNS6S | [M-2H]2− | 765.5 | 765.0 |
| [M-3H]3− | 510.0 | 509.9a | ||
| 6b | ΔUA2S-GlcNS6S-IdoA2S-GlcNS6S-GlcA-GlcNS6S | [M-2H]2− | 824.5 | 824.2 |
| [M-3H]3− | 549.3 | 549.3a | ||
| 6c | ΔUA2S-GlcNS6S-IdoA-GlcNAc6S-GlcA-GlcNS3S6S | [M-2H]2− | 805.5 | 804.8 |
| [M-3H]3− | 536.7 | 536.6a | ||
| 8s | ΔUA2S-GlcNS6S-IdoA2S-GlcNS6S-IdoA2S-GlcNS6S-IdoA2S-GlcNS | [M-3H]3− | 741.7 | 741.6 |
| [M-4H]4− | 556.0 | 556.0a | ||
| 8b | ΔUA2S-GlcNS6S-IdoA2S-GlcNS6S-IdoA2S-GlcNS6S-GlcA-GlcNS6S | [M-3H]3− | 741.7 | 742.1b |
| [M-4H]4− | 556.0 | 556.4a | ||
| 8c | ΔUA2S-GlcNS6S-IdoA2S-GlcNS6S-IdoA2S-GlcNS6S-IdoA2S-GlcNS6S | [M-4H]4− | 576.0 | 576.1a |
| [M-3H]3− | 768.3 | 768.1b | ||
| 8d | ΔUA2S-GlcNS6S-IdoA2S-GlcNS6S-IdoA-GlcNAc6S-GlcA-GlcNS3S6S | [M-4H]4− | 546.5 | 546.7a |
| [M-3H]3− | 729.0 | 728.9b | ||
| 10a | ΔUA2S-GlcNS6S-[-IdoA2S-GlcNS6S-]3-GlcA-GlcNS6S | [M-5H]5− | 561.0 | 559.9a |
| [M-4H]4− | 700.3 | 700.2b | ||
| 10b | ΔUA2S-[-GlcNS6S-IdoA2S-]4-GlcNS6S | [M-5H]5− | 576.0 | 576.4a |
| [M-S-5H]5− | 560.0 | 560.1 | ||
| 10c | ΔUA2S-[-GlcNS6S-IdoA2S-]2-GlcNS6S-IdoA-GlcNAc6S-GlcA-GlcNS3S6S | [M-5H]5− | 552.4 | 553.0a |
| [M-S-5H]5− | 536.4 | 537.0 | ||
| 12a | ΔUA2S-[-GlcNS6S-IdoA2S-]5-GlcNS6S | [M-6H]6− | 576.0 | 575.9a |
| [M-5H]5− | 691.4 | 691.1b | ||
| 12b | ΔUA2S-[-GlcNS6S-IdoA2S-]3-GlcNS6S-IdoA-GlcNAc6S-GlcA-GlcNS3S6S | [M-6H]6− | 556.3 | 556.3 |
| [M-5H]5− | 667.8 | 667.6b | ||
| [M-S-6H]6− | 543.0 | 543.1a | ||
| 14a | ΔUA2S-[-GlcNS6S-IdoA2S-]6-GlcNS6S | [M-7H]7− | 576.0 | 575.7 |
| [M-2S-7H]7− | 553.1 | 553.1a | ||
| 14b | ΔUA2S-[-GlcNS6S-IdoA2S-]4-GlcNS6S-IdoA-GlcNAc6S-GlcA-GlcNS3S6S | [M-7H]7− | 559.1 | 559.0 |
| [M-6H]6− | 652.5 | 652.6 | ||
| [M-2S-7H]7− | 536.2 | 536.3a | ||
| 16a | ΔUA2S-[-GlcNS6S-IdoA2S-]7-GlcNS6S | [M-8H]8− | 576.0 | 576.4 |
| [M-7H]7− | 658.4 | 658.6a,b | ||
| 16b | ΔUA2S-[-GlcNS6S-IdoA2S-]5-GlcNS6S-IdoA-GlcNAc6S-GlcA-GlcNS3S6S | [M-7H]7− | 641.5 | 641.9a,b |
| [M-6H]6− | 748.7 | 748.5b | ||
aBase peak.
bMass deduced from the protonated complex of oligosaccharides with TBA.
-S, SO3 moiety (80 U) lost from molecular ion.