Table 3.
Comparison of analytical results across four laboratories.
| VPs | VP Form | Lab-A (µg/L) * | Lab-B (µg/g) ** | Lab-C (µg/g) | Our Lab (µg/g) |
|---|---|---|---|---|---|
| Guaiacol | Free | 6.7 | 9 | 7 | 6 |
| Bound | 8.3 | 3.7 | 51 | 16 | |
| 4-methylguaiacol | Free | <1 | 1.7 | <5 | 1.1 |
| Bound | 2 | - | <5 | 3.5 | |
| Syringol | Free | 1 | <2 | <3 | 5.1 |
| Bound | 52 | 37 | 48 | 41 | |
| 4-methylsyringol | Free | <1 | <2 | <5 | < 1 |
| Bound | 9.7 | 3 | 8 | 9.0 | |
| o-cresol | Free | 4 | 7.7 | <3 | 3.5 |
| Bound | <1 | - | 4 | 2.7 | |
| p-cresol | Free | <1 | 2 | 7 | 1 |
| Bound | 1.3 | - | 4 | 5.5 | |
| m-cresol | Free | 3 | 6 | <3 | 2.6 |
| Bound | 2 | - | 8 | 3.6 |
* Calculated based on the liquid volume obtained after homogenization of grape berries. ** Bound VPs measured were guaiacol rutinoside, methylguaiacol rutinoside, syringol gentiobioside and methylsyringol gentiobioside for guaiacol, 4-methylguaiacol, syringol, and 4-methylsyringol, respectively.