Table 2.
Putative identifications of the three pollock ions identified in Fig. 4 and the ion found to be most significant for the separation of the other four species of fish in the chemometric models
| Species | m/z (Da) | Collision energy (V) | Ion | Lipid class | Fragment (s) (m/z–Da) | Putative identification |
|---|---|---|---|---|---|---|
| Cod | 788.5 | 30 | [M-H]− | PE | 327.24 | 22:6/18:1 |
| 281.25 | ||||||
| 153.00 | ||||||
| PS | 283.26 | 18:1/18:0 | ||||
| 281.25 | ||||||
| 153.00 | ||||||
| PS | 309.28 | 20:1/16:0 | ||||
| 255.23 | ||||||
| 153.00 | ||||||
| Coley | 817.5 | 35 | N/A | N/A | 327.24 | N/A |
| 283.25 | ||||||
| 281.25 | ||||||
| 255.23 | ||||||
| 229.20 | ||||||
| Haddock | 810.5 | 35 | [M-H]− | PE | 327.24 | 22:6/20:4 |
| 303.24 | ||||||
| 283.25 | ||||||
| 153.00 | ||||||
| PE | 301.22 | 22:5/20:5 | ||||
| 257.23 | ||||||
| 153.00 | ||||||
| PS | 303.24 | 20:4/18:0 | ||||
| 283.25 | ||||||
| 153.00 | ||||||
| Pollock | 629.5 | 20 | N/A | N/A | 327.24 | N/A |
| 301.22 | ||||||
| 283.25 | ||||||
| 655.5 | 15 | [2M-H]− | FA | 327.24 | 22:6 | |
| 283.25 | ||||||
| 229.20 | ||||||
| 667.5 | 25 | N/A | N/A | 339.21 | N/A | |
| 327.24 | ||||||
| 301.22 | ||||||
| 283.25 | ||||||
| 257.24 | ||||||
| Whiting | 790.5 | 30 | [M-H]− | PE | 327.24 | 22:6/18:0 |
| 283.25 | ||||||
| PS | 283.25 | 18:0/18:0 | ||||
| N/A | N/A | 701.42 | N/A | |||
| 480.33 | ||||||
| 463.24 | ||||||
| 255.25 |
Two different classes of phospholipids; phosphatidylethanolamine (PE) and phosphatidylserine (PS) were found to be the most likely identification for the ions with the only exception being the pollock ion m/z 655.5 which is believed to be a dimer of docosahexaenoic acid (DHA) (m/z 327.21 [M-H]−)