Table 4.
Retention time (Rt), wavelengths of maximum absorption in the visible region (λmax), mass spectral data and tentative identification, and phenolic compounds quantification (mg g of extract) in okra pods.
| Peak | Rt (min) | λmax (nm) | Molecular Ion[M − H]− (m/z) | MS2 (m/z) | Tentative Identification | Quantification |
|---|---|---|---|---|---|---|
| 1 | 14.84 | 354 | 625 | 301(100) | Quercetin-dihexoside | 0.785 ± 0.001 |
| 2 | 15.75 | 353 | 595 | 301(100) | Quercetin-O-pentosyl-hexoside | 0.90 ± 0.020 |
| 3 | 18.67 | 353 | 463 | 301(100) | Quercetin-3-O-glucoside | 1.500 ± 0.010 |
| 4 | 19.69 | 352 | 505 | 463(23), 301(100) | Quercetin-O-acetylhexoside | 0.628 ± 0.001 |
| 5 | 20.27 | 350 | 505 | 463(35), 301(100) | Quercetin-O-acetylhexoside | 0.175 ± 0.003 |
| 6 | 22.13 | 340 | 447 | 285(100) | Kaempferol-3-O-glucoside | 0.139 ± 0.004 |
| 7 | 32.81 | 314 | 593 | 285(100) | Kaempferol-O-caffeoyl-deoxyhexoside | 0.463 ± 0.002 |
| 8 | 37.98 | 314 | 635 | 489(21), 285(100) | Kaempferol-O-deoxyhexoside-O-acetyl-caffeoyl | 0.148 ± 0.001 |
| Total phenolic compounds | 4.740 ± 0.030 |
Standard calibration curve used for all the flavonols: quercetin 3-O-glucoside (y = 34843 x − 160173; R2 = 0.9998; LOD = 0.21 μg/mL; LOQ = 0.71 μg/mL). Linearity was performed with 11 levels calibration curve (0.1–100 μg/mL).