Table 4. Stock Solution Stability of HHC and IS at −30 ± 10 °C for 22 days (Mean ± SD, n = 3).
| analyte (nominal conc., ng/mL) | observed conc. (ng/mL) | accuracy (%) | precision (CV%) |
|---|---|---|---|
| fresh | |||
| HHC (375.00) | 375.00 ± 18.19 | 100 | 4.85 |
| IS (110.10) | 110.10 ± 1.38 | 100 | 1.25 |
| stock stability for 22 days | |||
| HHC (375.00) | 398.08 ± 1.45 | 106.15 | 0.36 |
| IS (110.10) | 112.08 ± 0.90 | 101.80 | 0.80 |