Table 4.
Stability of five alkaloids under the tested conditions.
| Compound | Nominal Concentration (ng/mL) | Freeze–Thaw Stability | Long-Term Stability | Bench-Top Stability | Post-Preparative Stability | ||||
|---|---|---|---|---|---|---|---|---|---|
| RE (%) | RSD (%) | RE (%) | RSD (%) | RE (%) | RSD (%) | RE (%) | RSD (%) | ||
| Protopine | 1.875 | 12.6 | 1.9 | 12.6 | 0.9 | 12.1 | 2.7 | 11.9 | 2.0 |
| 22.5 | −3.9 | 1.7 | −4.9 | 1.9 | −5.4 | 1.7 | −2.5 | 2.2 | |
| Chelidonine | 1.250 | 5.2 | 2.4 | 8.2 | 2.1 | 7.8 | 2.5 | 8.2 | 2.4 |
| 15.0 | −8.9 | 3.4 | −7.1 | 1.6 | −9.6 | 2.3 | −6.3 | 2.2 | |
| Coptisine | 31.25 | 5.2 | 1.9 | 12.3 | 3.5 | 9.5 | 0.8 | 8.0 | 1.9 |
| 375 | −11.7 | 3.2 | −11.5 | 0.9 | −10.4 | 3.9 | −9.3 | 2.5 | |
| Sanguinarine | 50.0 | −4.8 | 1.7 | −3.8 | 2.6 | 2.2 | 0.5 | −4.1 | 1.6 |
| 600 | −6.3 | 1.5 | −6.0 | 1.5 | −5.3 | 2.3 | −4.4 | 1.7 | |
| Chelerythrine | 15.0 | −13.3 | 3.7 | −10.2 | 3.5 | −12.7 | 4.2 | −12.0 | 1.0 |
| 180 | 8.2 | 3.6 | 6.5 | 2.9 | 4.5 | 3.1 | 8.4 | 2.0 | |