Table 3.
Storage Condition | Concentration (μmol/L) | Mean ± SD | Relative SD (%) |
---|---|---|---|
0.2 | 0.20 ± 0.02 | 7.56 | |
4 °C temperature for 24 h | 50 | 53.21 ± 2.20 | 4.12 |
80 | 82.27 ± 4.04 | 4.91 | |
0.2 | 0.20 ± 0.02 | 9.51 | |
Room temperature (25 °C) for 24 h | 50 | 51.94 ± 2.18 | 4.20 |
80 | 80.08 ± 5.38 | 6.72 | |
0.2 | 0.19 ± 0.01 | 7.51 | |
−40 °C temperature for 30 days | 50 | 51.62 ± 1.88 | 3.65 |
80 | 81.21 ± 3.42 | 4.21 | |
0.2 | 0.20 ± 0.02 | 8.01 | |
Three freeze-thaw cycles | 50 | 52.41 ± 2.31 | 4.41 |
(each at −40 °C for 24 h) | 80 | 80.56 ± 3.78 | 4.81 |