Table 3.
Phenolic acids in oak woods.
| Compounds | Sample | λ (Max) | MW | ESI-MS/MS Prominent Ions (m/z) | References |
|---|---|---|---|---|---|
| Hydroxybenzoic Acids | |||||
| Gallic acid | A, B, D–I | 270 | 170 | 169 [M-H]−, 154, 125, 81, 79 | [5,40,50,51,52,53,54,55,56] |
| Gentisic acid | B | 340 | 154 | 153 [M-H]−, 109 | [50] |
| p-Hydroxybenzoic acid | H | 255 | 138 | 137 [M-H]−, 93 | [55] |
| Protocatechuic acid | A, B, H | 259, 293 | 154 | 153 [M-H]−, 109 | [40,50,55] |
| Syringic acid | B, D–I | 275 | 198 | 197 [M-H]−, 182, 167, 153, 138 | [5,50,51,52,53,54,55] |
| Vanillic acid | A, B, D–G, I | 260, 291 | 168 | 167 [M-H]−, 152, 123, 108 | [40,50] |
| p-Hydroxybenzoic aldehyde | B | 280, 254 | 122 | 121 [M-H]− | [50] |
| Protocatechuic aldehyde | A, B, H | 280, 310 | 138 | 137 [M-H]− | [40,50] |
| Syringaldehyde | A, C–I | 307 | 182 | 181 [M-H]−, 166, 151 | [40,51,52,53,54,55,56,57] |
| Vanillin | A–I | 304 | 152 | 151 [M-H]−, 136, 108 | [5,40,50,51,52,53,54,55,56,57] |
| Hydroxycinnamic Acids | |||||
| p-Coumaric acid | A, B, G | 310 | 164 | 163 [M-H]−, 119, 94 | [40,50,54] |
| Caffeic acid | A, B | 324 | 180 | 179 [M-H]−, 135 | [40,50] |
| Ferulic acid | A, B, E, F | 280, 340 | 194 | 193 [M-H]−, 178, 149, 134 | [5,40,50,53] |
| Sinapic acid | A, B | 340 | 222 | 221 [M-H]−, 164, 149, 121 | [40,50] |
| Sinapaldehyde | A, D–F, I | 254 | 208 | 207 [M-H]−, 192, 189 | [5,40,51,52,53,56] |
| Coniferaldehyde | A, D–F, I | 260 | 178 | 177 [M-H]−, 162, 159, 147 | [5,40,51,52,53,56] |
| Eugenol | D, E, G | 230 | 164 | 163 [M-H]−, 149, 137 | [51,52,54] |
A: Toasted and non-toasted oak wood samples (American, French, Hungarian, Rumanian and Russian oak woods); B: Oak aged wine samples (American, French and Hungarian oak woods aged over 12 months); C: Oak wood samples; D: Oak aged sugarcane spirit samples; E: Green oak samples (Spanish oak wood); F: Natural seasoning and tasted oak wood samples (American, French and Spanish oak woods); G: Oak aged sugarcane spirit samples (Quercus spp. oak wood aged over 12 months); H: Oak aged rum samples (Oak wood aged over 15 years); and I: Oak chips samples (American oak wood).