| Conditions |
Nominal
concentration
(ng/mL) |
Observed concentration (ng/mL) |
Difference (%)
between reference
and test |
Mean of reference
(n=6) |
Mean of test
(n=6) |
Storage of samples at
room temperature for 18 hr |
6 |
5.5 |
5.2 |
-5.4 |
| 1600 |
1430.7 |
1363.0 |
-4.7 |
| Three freeze-thaw cycles
(- 70°C) |
6 |
6.0 |
5.8 |
-3.3 |
| 1600 |
1500.8 |
1491.0 |
-0.7 |
Storage of extracted samples
in autosampler at 4°C for 36 hr |
6 |
6.2 |
6.3 |
1.6 |
| 1600 |
1624.3 |
1612.0 |
-0.8 |
