Table 1 Retention times, ultraviolet–visible absorption maxima, and mass spectral data of phenolic acids and flavonoids in leaves of lettuce cultivars
Peak no | tR (min) | UV λmax (nm) | Neutral mass (Da) | Observed m/z [M-H] | Dimer and fragment ions in ESI/MS/MS | Mass error, ppm | Identification |
|---|---|---|---|---|---|---|---|
1 | 1.32 | 300sh, 326 | 354.0951 | 353.08698 | 707.18302 [2M-H]−, 191.05512 [Quin-H]−, 85.02891 | − 2.3 | 1-O-Caffeoylquinic acid (1-CQA) |
2 | 1.54 | 300sh, 324 | 354.0951 | 353.08674 | 707.18124 [2M-H]−, 191.05503 [Quin-H]−, 179.03365 | − 3.0 | 3-O-Caffeoylquinic acid (3-CQA) |
3 | 2.39 | 300sh, 324 | 354.0951 | 353.08697 | 707.18302[2M-H]−, 191.05512[Quin-H]−, 85.02891 | − 2.4 | 5-O-Caffeoylquinic acid (5-CQA) |
4 | 4.64 | 328 | 368.1107 | 367.1025 | 191.05493, 134.03524 | − 2.6 | 5-Feruloylquinic acid (5-FQA) |
5 | 6.62 | 301sh, 324 | 474.0798 | 473.0719 | 947.15066 [2M-H]-, 311.03986 [Caftar-H]−, 293.02929 [Caftar-H-H2O]−, 179.03366 [Caffeic–H]−, 149.00859 [Tartaric–H]− 133.02836, 112.98729 | − 1.4 | Dicaffeoyltartaric acid (DCTA) |
6 | 7.36 | 328 | 462.0798 | 461.07175 | 285.03951, 133.02837 | − 1.7 | Kaempferol glucuronide (KGR) |
7 | 7.79 | 252, 360 | 550.09587 | 549.08832 | 1099.18568 [2M-H]−, 505.09879 [M-H-CO2], 300.02672 [Yo-H], 271.02369, 255.02863 [Yo-CHO-OH]− | − 0.5 | Quercetin malonylglucoside (QMG) |
8 | 8.66 | 330 | 516.1268 | 515.1190 | 1031.24625 [2M-H], 353.08678[Cafquin-H], 191.05486 [Quin-H]-, 179.03376 [Caffeic-H]-, 135.4416 [Caffeic-H–CO2] | − 1.0 | Dicaffeoylquinic acid (DCQA) |
9 | 8.88 | 348 | 534.1009 | 533.09327 | 489.10292, 285.03897 [luteolin-H]-284.03133, 133.02831 | − 0.7 | Kaempferol malonylglucoside (KMG) |
10 | 9.53 | 328 | 476.0955 | 475.08749 | 951.18882 [2M-H], 299.05492, 285.03121, 284.03121 | − 1.5 | Methylkaempferol glucuronide (MKGR) |