Table 2.
Calibration curves, test range, limit of detection (LOD), limit of quantification (LOQ), precision, and repeatability for the six analytes.
| Analytes | Calibration Curves | R2 | Linear Range (μg/mL) | Precision (RSD, %) | LOQ ng/mL | LOD ng/mL | Repeatability (RSD, %, n = 6) | |
|---|---|---|---|---|---|---|---|---|
| Intra-Day | Inter-Day | |||||||
| Monotropein | Y = 0.0492X + 0.0072 | 0.9981 | 0.015–79.65 | 1.71 | 3.80 | 13.87 | 4.20 | 2.89 |
| Deacetyl asperulosidic acid | Y = 0.0281X + 0.001 | 0.9990 | 0.030–96.00 | 2.80 | 3.83 | 26.63 | 8.07 | 3.92 |
| Asperulosidic acid | Y = 0.0252X + 0.0018 | 0.9956 | 0.042–21.00 | 1.12 | 2.56 | 27.57 | 9.19 | 2.54 |
| Asperuloside | Y = 0.1235X + 0.0073 | 0.9987 | 0.018–37.50 | 2.71 | 2.74 | 11.06 | 3.35 | 3.17 |
| Rubiadin-1-methyl ether | Y = 1.1937 X + 0.2136 | 0.9930 | 0.008–21.75 | 2.50 | 4.21 | 6.74 | 2.04 | 4.02 |
| Rubiadin | Y = 0.587X + 0.0233 | 0.9949 | 0.003–22.50 | 0.75 | 2.72 | 2.60 | 0.87 | 2.35 |