Table 3.
Stability of FA and 5-M-THF in plasma under different storage conditions (n=3).
| Storage conditions | Analytes | Concentration levels (ng/mL) |
RSD (%) | RE (%) | |
|---|---|---|---|---|---|
| Nominal | Determined | ||||
| FA | 0.595 | 0.580 | 4.7 | −2.6 | |
| Residue stability | 15.9 | 16.5 | 1.4 | 3.9 | |
| (1 h, room temperature) | 5-M-THF | 12.1 | 13.2 | 1.4 | 8.8 |
| 42.4 | 46.3 | 1.1 | 9.1 | ||
| FA | 0.595 | 0.637 | 6.2 | 7.1 | |
| Short-term stability | 15.9 | 16.7 | 3.2 | 5.3 | |
| (7.5 h, room temperature) | 5-M-THF | 12.1 | 12.4 | 0.6 | 2.1 |
| 42.4 | 44.2 | 1.3 | 4.3 | ||
| FA | 0.595 | 0.587 | 6.4 | −1.4 | |
| Freeze/thaw stability | 15.9 | 14.8 | 0.5 | −7.2 | |
| (three cycles) | 5-M-THF | 12.1 | 12.8 | 4.5 | 5.2 |
| 42.4 | 46.0 | 5.0 | 8.3 | ||
| FA | 0.595 | 0.658 | 6.8 | 10.6 | |
| Long-term stability | 15.9 | 16.9 | 4.1 | 6.3 | |
| (50 days, −80 °C) | 5-M-THF | 12.1 | 10.8 | 2.6 | −10.8 |
| 42.4 | 41.2 | 4.6 | −2.9 | ||
| FA | 0.595 | 0.617 | 6.7 | 3.8 | |
| Autosampler stability | 15.9 | 17.2 | 2.9 | 8.1 | |
| (10 h, 4 °C) | 5-M-THF | 12.1 | 12.3 | 7.8 | 1.5 |
| 42.4 | 43.1 | 0.8 | 1.6 | ||
| FA | 0.595 | 0.566 | 6.1 | −4.9 | |
| Supernatant stability | 15.9 | 16.6 | 7.9 | 4.5 | |
| (12 h, room temperature) | 5-M-THF | 12.1 | 13.0 | 1.9 | 7.6 |
| 42.4 | 46.4 | 3.5 | 9.4 | ||
| FA | 0.595 | 0.580 | 3.5 | −2.6 | |
| Supernatant stability | 15.9 | 14.8 | 4.2 | −2.0 | |
| (24 h, −80 °C) | 5-M-THF | 12.1 | 12.3 | 6.4 | 1.2 |
| 42.4 | 44.8 | 3.0 | 5.6 | ||