Table 2.
Regression equations, linearity ranges, correlation coefficients, limits of quantitation (LOQ), limits of detection (LOD), and inter-day and intra-day precisions and stability for 12 analytes using the QDa detector.
| Peak No. | Analytes | Calibration Curves | R2 | Linear Ranges (μg/mL) |
LOQ (μg/mL) |
LOD (μg/mL) |
Precisions (%, RSD) | Stability (%, RSD) |
Recovery | ||
|---|---|---|---|---|---|---|---|---|---|---|---|
| Intra-Day (n = 6) |
Inter-Day (n = 3) |
Mean Recovery (%) |
RSD (%) | ||||||||
| 1 | 3,4-dihydroxybenzoic acid | y = 12.26x + 7.06 | 0.9991 | 0.01–22.00 | 0.005 | 0.001 | 2.73 | 3.19 | 1.50 | 104.64 | 2.21 |
| 2 | 5-O-caffeoylquinic acid | y = 1.01x + 0.56 | 0.9995 | 1.20–23.50 | 0.34 | 0.11 | 4.80 | 4.54 | 2.77 | 105.13 | 3.10 |
| 3 | 3-O-caffeoylquinic acid | y = 0.57x + 0.77 | 0.9995 | 1.56–45.70 | 0.41 | 0.13 | 4.40 | 4.41 | 2.99 | 100.22 | 3.46 |
| 4 | caffeic acid | y = 4.17x + 1.57 | 0.9991 | 10.5–105.0 | 0.14 | 0.04 | 1.55 | 3.12 | 1.80 | 99.16 | 2.45 |
| 5 | 4-O-caffeoylquinic acid | y = 1.76x + 1.62 | 0.9991 | 6.50–65.00 | 0.06 | 0.02 | 1.37 | 3.68 | 2.00 | 102.98 | 3.58 |
| 7 | 3,5-O-dicaffeoylquinic acid | y = 6.43x + 0.66 | 0.9998 | 2.35–23.50 | 0.56 | 0.17 | 3.72 | 3.68 | 1.77 | 98.78 | 3.91 |
| 8 | luteoloside | y = 0.67x + 1.78 | 0.9991 | 3.47–34.70 | 0.30 | 0.09 | 2.26 | 3.47 | 2.31 | 102.77 | 2.67 |
| 9 | 3,4-O-dicaffeoylquinic acid | y = 0.79x + 0.41 | 0.9992 | 10.2–145.00 | 0.50 | 0.16 | 2.83 | 4.10 | 2.78 | 102.45 | 3.23 |
| 10 | rutin | y = 1.87x − 1.23 | 0.9991 | 8.83–22.07 | 0.19 | 0.05 | 1.86 | 2.92 | 2.96 | 99.69 | 2.44 |
| 11 | 4,5-O-dicaffeoylquinic acid | y = 4.24x + 1.00 | 0.9995 | 2.02–20.2 | 0.50 | 0.15 | 1.08 | 2.51 | 1.76 | 102.44 | 2.34 |