Table 1.
Structural information, retention time and the optimized LC-QqQ/MS parameters for analyzing target phenolic compounds.
| Compound (abbreviation) | Formula | Retention time (min) | MS/MS transition (dMRM) |
Fragmentor voltage (V) | Collision energy (V) | |
|---|---|---|---|---|---|---|
| Precursor ion (m/z) | Product ion (m/z) (quantifier/qualifier) | |||||
| C6C1 | ||||||
| Gallic acid (GA) | C7H6O5 | 2.24 | 169.0 | 125.0/79.1 | 86 | 12/24 |
| 3,4-Dihydroxybenzoic acid (3,4-diHBA) | C7H6O4 | 4.24 | 153.0 | 109.1/108.1 | 86 | 12/28 |
| 4-Hydroxybenzoic acid (4-HBA) | C7H6O3 | 7.11 | 137.0 | 93.1/80.1 | 74 | 16/20 |
| Hippuric acid (HA) | C9H9NO3 | 8.65 | 178.1 | 134.1/77.1 | 80 | 8/16 |
| Vanillic acid (VA) | C8H8O4 | 9.16 | 167.0 | 152.0/108.1 | 80 | 12/16 |
| 3-Hydroxybenzoic acid (3-HBA) | C7H6O3 | 9.91 | 137.0 | 93.1/N.D. | 74 | 16/8 |
| C6C2 | ||||||
| 3, 4-Dihydroxyphenylacetic acid (3,4-diHPAA) | C8H8O4 | 5.87 | 167.0 | 123.1/N.D. | 54 | 4/12 |
| 3-Hydroxyphenylaeetie acid (3-HPAA) | C8H8O3 | 10.75 | 151.0 | 107.1/105.0 | 48 | 4/0 |
| Homovanillic acid (HVA) | C9H10O4 | 11.22 | 181.1 | 137.1/122.1 | 58 | 4/12 |
| C6C3 | ||||||
| 3-(3,4-Dihydroxyphenyl)propionic acid (3,4-diHPPA) | C9H10O4 | 8.93 | 181.1 | 137.1/59.1 | 72 | 8/16 |
| Caffeic acid (GA) | C9H8O4 | 9.51 | 179.0 | 135.1/97.0 | 88 | 4/16 |
| Dihydrocoumaric acid (diHCA) | C9H10O3 | 13.87 | 165.1 | 119.1/121.1 | 88 | 12/8 |
| trons-p-Coumaric acid (p-CA) | C9H8O3 | 14.18 | 163.0 | 119.1/93.1 | 80 | 12/16 |
| 3-(3-Hydroxyphenyl)propionic acid (3-HPPA) | C9H10O3 | 15.56 | 165.1 | 121.1/106.1 | 88 | 16/20 |
| Ferulic acid (FA) | C10H10O4 | 15.96 | 193.1 | 178.1/134.1 | 88 | 8/24 |
| trans-Cinnamic acid-d7 (I.S.) | C9D8O2 | 16.22 | 154.2 | 110.1/82.2 | 74 | 8/20 |
| C6C5 | ||||||
| 5-(4-Hydroxyphenyl)valeric acid (4-HPVA) | C11H14O3 | 16.15 | 193.1 | 175.2/149.0 | 86 | 12/12 |
| Flavanol | ||||||
| Catechin (( + )-C) | C15H14O6 | 8.03 | 289.1 | 245.2/123.1 | 134 | 12/32 |
| Epicatechin (( − )-EC) | C15H14O6 | 11.88 | 289.1 | 245.2/203.1 | 134 | 12/20 |
I.S., internal standard.