Table 2.
Phenolic compound standards used for identification purposes: retention times (RT), exact mass-to-charge ratios (m/z), molecular formulae and error m/z (in ppm).
| Name | RT (min) program 2 |
Measured m/z |
Molecular formula | Calculated m/z |
Error m/z (ppm) | ESI-MSn m/z (Relative intensity, in %) |
|---|---|---|---|---|---|---|
| 7-hydroxy-6-methoxycoumarin 7-glucoside (scopolin, scopoletin 7-O-glucoside) | 10.3 | 355.1021 | C16H19O9+ | 355.1024 | -0.8 | MS2 [355]: 337 (11), 245 (3), 193 (100), 149 (1), 165 (1), 133 (12), 105 (5) MS3 [355→193]: 178 (16), 165 (21), 149 (11), 137 (6), 133 (100) |
| 353.0876 | C16H17O9- | 353.0867 | 2.5 | MS2 [353]:191 (100), 176 (9) MS3 [353→191]: 176 (100) |
||
| 7,8-dihydroxy-6-methoxycoumarin 8-glucoside (fraxin) | 13.0 | 371.0956 | C16H19O10+ | 371.0973 | -4.6 | MS2 [371]: 368 (11), 362 (13), 357 (12), 355 (66), 353 (35), 340 (13), 327 (23), 326 (25), 325 (195), 309 (15), 300 (17), 288 (10), 269 (19), 268 (11), 265 (11), 262 (14), 261 (17), 221 (12), 209 (100), 187 (19), 177 (14), 170 (19), 156 (15), 133 (24) MS3 [371→209]: 194 (100) |
| 369.0825 | C16H17O10- | 369.0816 | 2.4 | MS2 [369]: 207 (100), 192 (20) MS3 [369→207]: 192 (100), 163 (0.2) |
||
| 7,8-dihydroxy-6-methoxycoumarin (fraxetin) | 16.4 | 209.0444 | C10H9O5+ | 209.0445 | -0.5 | MS2 [209]: 194 (31), 181 (52), 177 (15), 165 (7), 163 (80), 153(9), 149 (100), 135 (13), 107 (18) |
| 207.0291 | C10H7O5- | 207.0288 | 1.4 | MS2 [207]: 192 (100), 163 (0.3) | ||
| 7-hydroxy-6-methoxycoumarin (scopoletin) | 20.0 | 193.0494 | C10H9O4+ | 193.0495 | -0.5 | MS2 [193]: 178 (8), 165 (31), 149 (12), 137 (12), 133 (100), 117 (2), 105 (3), 89 (3), 63 (6) |
| 191.0346 | C10H7O4- | 191.0339 | 3.7 | MS2 [191]: 176 (100), 148 (0.4) | ||
| 7-hydroxy-6,8-dimethoxycoumarin (isofraxidin) | 21.6 | 223.0594 | C11H11O5+ | 223.0601 | -3.1 | MS2 [223]: 208 (100), 207 (7), 195 (14), 191 (8), 190 (49), 179 (7), 163 (72), 162 (6), 135 (19) 107 (45) |
| 221.0443 | C11H9O5- | 221.0445 | -0.9 | MS2 [221]: 206 (100), 209 (0.5), 191 (5), 162 (0.8) | ||
| Ferulic acid | 23.0 | 195.0657 | C10H11O4+ | 195.0652 | 2.6 | MS2 [195]: 177 (100), 153 (4), 145 (3) |
| 193.0504 | C10H9O4- | 193.0495 | 4.7 | MS2 [193]: 178 (70), 149 (100), 139 (80) | ||
| 6-hydroxy-5,7-dimethoxycoumarin (fraxinol) | 23.8 | 223.0594 | C11H11O5+ | 223.0601 | -3.1 | MS2 [223]: 208 (100), 195 (11), 190 (40), 179 (6), 163 (54), 135 (19), 107 (39), 91 (4) |
| 221.0440 | C11H9O5- | 221.0444 | -1.8 | MS2 [221]: 206 (100), 191 (5), 209 (0.5), 162 (0.2) | ||
| Coniferyl aldehyde | 24.6 | 179.0706 | C10H11O3+ | 179.0703 | 1.7 | MS2 [179]: 161 (100), 147 (97), 133 (18), 119 (7), 105 (10) |
| 177.0554 | C10H9O3- | 177.0546 | 4.5 | MS2 [177]: 162 (100), 163 (1), 158 (0.3) | ||
| Sinapyl aldehyde | 25.1 | 209.0810 | C11H13O4+ | 209.0808 | 1.0 | MS2 [209]: 191 (47), 181 (10), 177 (100), 153 (7), 149 (20), 145 (15), 131 (12), 121 (17), 103 (5) |
| 207.0662 | C11H11O4- | 207.0652 | 4.8 | MS2 [207]: 192 (100), 191 (0.3), 177 (2), 147 (0.2), 133 (0.2) |
The m/z ratios of parent and fragment ions were determined from the data in the HPLC/ESI-MS(TOF) and HPLC/ESI-MS(ion trap) chromatograms, respectively, working in both positive and negative mode. Common names for coumarins and their glucosides are indicated in brackets. The parent ion m/z ratios correspond to [M+H]+ and [M-H]-. The major ion of the MS2 and MS3 spectra is indicated in bold.