Storage condition | Nominal concentration (ng/mL) | Measured concentration (ng/mL) | Recovery (%) |
Short-term stability (6 h in plasma) | 30 | 18,749* | 108.53 |
600 | - | - | |
960 | 582,694* | 89.00 | |
Autosampler stability after 65 h | 30 | 29.53 | 99.53 |
600 | - | - | |
960 | 918.43 | 98.37 | |
Freeze-thaw cycles (N = 5) | 30 | 31.70 | 105.67 |
600 | 602.13 | 100.36 | |
960 | 1039.94 | 108.33 | |
Long term stability (198 day, −80˚C) | 30 | 29.80 | 99.34 |
600 | 582.82 | 97.14 | |
960 | 945.21 | 98.46 |