Table 4.
Mass spectral data for identification of phenolic compounds in LE by Liquid Chromatography–Mass Spectrometry (LC–IT/MS).
| Polyphenol Subclass (Flavonoids) |
Compound Name | Retention Time (min) | Positive Ions (m/z) | ||||
|---|---|---|---|---|---|---|---|
| MW | [M+H]+ | [M+Na]+ | [M+K]+ | In-Source Fragments | |||
| flavanols | (-)-Epicatechin a | 10.0 | 290 | 291 | -- | -- | -- |
| flavanols | (+)-Catechin a | 12.3 | 290 | 291 | -- | -- | -- |
| flavonols | Kaempferol derivative b | 19.4 | 742 | 743 | 765 | -- | -- [Aglycone+H]+ = 287, [Aglycone+H-H2O]+ = 269 |
| flavonols | Kaempferol derivative c | 19.8 | 902 | 903 | 925 | -- | [(M-Rham)+H]+ = 757 [(M-Rham-Glc)+H]+ = 595 [(M-Rham-2Glc)+H]+ = 433 [Aglycone+H]+ = 287, [Aglycone+H-H2O]+ = 269 |
| flavonols | Quercetin derivative b | 18.8 | 625 | 627 | -- | -- | [(M-Glc)+H]+ = 463 [Aglycone+H]+ = 303, [Aglycone+H-H2O]+ = 285 |
| flavonols | Quercetin derivative b | 20.5 | 609 | 611 | 633 | 649 | [Aglycone+H]+ = 303, [Aglycone+H-H2O]+ = 285 |
m/z values for the base peak are given in bold type. (a) Identification by comparison with the pure standard. (b) Identification by in source-fragmentation and by searching in online databases such as FOODB (http://foodb.ca) and METLIN (http://metlin.scripps.edu). (c) Identification by comparison with bibliography: kaempherol-3-O-[rhamnosyl-glucosylglucoside]-7-O-rhamnoside [32].