Table 2. Tentative identities of ions with high discriminatory capacity in the durum vs. bread wheat OPLS-DA model.
| Ion Identifier | Ion RT | Ion m/z | Adduct | Adduct Mass | Dppm | Tentative Identity | Empirical Formula | Class | Overexpressed In: | Broad Class |
| 0.49_104.1077 | 0.49 | 104.1077 | [M+H+Na]2+ | 184.2191 | 0 | Tridecane | C13H28 | FA | BW | NP |
| 7.43_339.2898 | 7.43 | 339.2898 | [M+H−H2O]+ | 356.2926 | 0 | Heneicosanedioic acid, 6 MG derivatives | C21H40O4 | FA | BW | NP |
| 6.14_349.3104 | 6.14 | 349.3104 | [M+3H]3+ | 1044.9085 | 0 | 7 TG derivatives | C69H120O6 | GL | BW | PL |
| 2.34_353.228 | 2.34 | 353.2280 | [M+2Na]2+ | 660.4754 | 3 | 3 DG derivatives | C43H64O5 | GL | BW | PL |
| 6.58_377.3415 | 6.58 | 377.3415 | [M+H−2H2O]+ | 412.3553 | 2 | 2 MG derivatives | C25H48O4 | GL | BW | PL |
| 7.41_595.5318 | 7.41 | 595.5318 | [M+H]+ | 594.5223 | 3 | 12 DG derivatives | C37H70O5 | GL | BW | PL |
| 7.07_617.5147 | 7.07 | 617.5147 | [M+H]+ | 616.5067 | 1 | 21 DG derivatives | C39H68O5 | GL | BW | PL |
| 7.42_937.6763 | 7.42 | 937.6763 | [M+K]+ | 898.7050 | 8 | 8 TG derivatives | C59H94O6 | GL | BW | PL |
| 8.50_719.4624 | 8.50 | 719.4624 | [M+Na]+ | 696.4730 | 0 | 2 PA derivatives | C39H69O8P | GP | BW | PL |
| 8.50_741.4486 | 8.50 | 741.4486 | [M+2Na−H]+ | 696.4730 | 6 | 2 PA derivatives | C39H69O8P | GP | BW | PL |
| 7.07_782.536 | 7.07 | 782.5360 | [M+CH3OH+H]+ | 749.4996 | 3 | 3 PC derivatives, 2 PE derivatives | C42H72NO8P | GP | BW | PL |
| 7.42_803.5648 | 7.42 | 803.5648 | [M+H]+ | 802.5598 | 2 | PG(17∶0/20∶4(5Z,8Z,11Z,14Z)) | C43H81NO10P | GP | BW | PL |
| 7.40_936.6635 | 7.40 | 936.6635 | NC | NC | BW | |||||
| 7.40_941.6199 | 7.40 | 941.6199 | NC | NC | BW | |||||
| 7.08_958.6475 | 7.08 | 958.6475 | NC | NC | BW | |||||
| 7.09_963.6014 | 7.09 | 963.6014 | NC | NC | BW | |||||
| 1.67_325.1129 | 1.67 | 325.1129 | [M+H+Na]2+ | 626.2296 | 0 | Tetrahydropteroyltri-L-glutamate | C24H34N8O12 | FA | DW | NP |
| 2.25_365.316 | 2.25 | 365.3160 | [M+K]+ | 326.3549 | 5 | Behenyl alcohol | C22H46O | FA | DW | NP |
| 2.38_381.3093 | 2.38 | 381.3093 | [M+Na]+ | 358.3236 | 9 | 3,7,11,15,19-Pentamethyleicosa-2E,6E,10E,14E,18-pentaen-1-ol; 15-methyl-1,2-heneicosanediol | C25H42O | FA | DW | NP |
| 2.46_381.3096 | 2.46 | 381.3096 | [M+Na]+ | 358.3236 | 8 | 3,7,11,15,19-Pentamethyleicosa-2E,6E,10E,14E,18-pentaen-1-ol; 15-methyl-1,2-heneicosanediol | C25H42O | FA | DW | NP |
| 2.08_393.2754 | 2.08 | 393.2754 | [M+K]+ | 354.3134 | 2 | 4 oxodocosanoic acid derivatives | C22H42O3 | FA | DW | NP |
| 3.75_494.3259 | 3.75 | 494.3259 | [M+CH3OH+H]+ | 461.2930 | 1 | AMC arachidonoyl amide | C30H39NO3 | FA | DW | NP |
| 3.59_518.3227 | 3.59 | 518.3227 | [M+2Na-H]+ | 473.3505 | 1 | Docosa-4,7,10,13,16-pentaenoyl carnitine, clupanodonyl carnitine | C29H47NO4 | FA | DW | NP |
| 2.23_361.2844 | 2.23 | 361.2844 | [M+2H]2+ | 720.5543 | 0 | 7 PC derivatives | C39H79NO8P | GP | DW | PL |
| 3.59_518.3227 | 3.59 | 518.3227 | [M+Na]+ | 495.3325 | 1 | 5 PC derivatives | C24H50NO7P | GP | DW | PL |
| 2.46_363.3007 | 2.46 | 363.3007 | NC | NC | DW | |||||
| 1.66_533.1525 | 1.66 | 533.1525 | [M+2Na-H]+ | 488.1835 | 4 | Sericetin diacetate | C29H28O7 | PK | DW | PL |
| 3.94_1039.664 | 3.94 | 1039.6640 | [M+2Na−H]+ | 994.6944 | 1 | Dodecaprenyl diphosphate | C60H100O7P2 | PR | DW | PL |
| 5.21_337.2678 | 5.21 | 337.2678 | [M+H−2H2O]+ | 372.2777 | 8 | Steroid derivative (structurally similar to Finasteride) | C23H36N2O2 | ST | DW | NP |
| 2.20_377.2804 | 2.20 | 377.2804 | [M+CH3OH+H]+ | 344.2464 | 1 | 6 steroid derivatives (structurally similar to hydroxystanozolol or epistanolozolol) | C21H32N2O2 | ST | DW | NP |
| 2.30_379.2931 | 2.30 | 379.2931 | [M+Li]+ | 372.2777 | 1 | Steroid derivative (structurally similar to Finasteride) | C23H36N2O2 | ST | DW | NP |
| 2.24_379.294 | 2.24 | 379.2940 | [M+Li]+ | 372.2777 | 0 | Steroid derivative (structurally similar to Finasteride) | C23H36N2O2 | ST | DW | NP |
| 2.22_395.2897 | 2.22 | 395.2897 | [M+Li]+ | 388.2726 | 2 | Steroid derivative (structurally similar to o-Hydroxyfinasteride) | C23H36N2O3 | ST | DW | NP |
| 6.96_413.3784 | 6.96 | 413.3784 | [M+H−H2O]+ | 430.3811 | 0 | 8 Vitamin D3 derivatives | C29H50O2 | ST | DW | NP |
| 2.21_417.2756 | 2.21 | 417.2756 | [M+Na]+ | 394.2872 | 1 | Vitamin D3 derivative | C27H38O2 | ST | DW | NP |
| 6.28_427.3589 | 6.28 | 427.3589 | [M+H−2H2O]+ | 462.3709 | 1 | Vitamin D3 derivative | C29H50O4 | ST | DW | NP |
The METLIN: Metabolite and Tandem MS Database was used to assign tentative compound identities and empirical formulas to the 33 influential ions with maximal m/z error set at 10 ppm under positive ionization adduct scan modes. Tentative identities for each ion were chosen based on smallest accurate mass error (AME) compared to the queried ion m/z; in the event of an AME tie, adducts with same AME but different empirical formulas are reported. Table columns: Ion Identifier = identifier used in Figure 4 , Panel 4B; Ion RT = ion retention time in minutes; Ion m/z = ion mass-to-charge ratio in daltons; Adduct = positive ionization adduct; Adduct Mass = mass of ion + adduct; Dppm = change (Δ, or d) in ppm from Ion m/z, used to determine AME; Tentative Identity = identifier with smallest AME from potential hits; Empirical Formula = derived from Adduct Mass and Dppm; Class = class assignation according to the Lipid Maps Lipidomics Gateway as: 1) fatty acyls (FA), 2) glycerolipids (GL), 3) glycerophospholipids (GP), 4) sphingolipids (SP), 5) sterol lipids (ST), 6) prenol lipids (PR), 7) saccharolipids (SL), 8) polyketides (PK), or NC if tentative identities could not be matched to the ion m/z; Overexpressed in: = ion spectral intensity higher in bread wheat (BW) or durum wheat (DW) as indicated.