Storage condition

Nominal concentration (ng/mL)

Measured concentration (ng/mL)

Recovery (%)

Short term stability (6 h in plasma)

0.30

29381^*

101.82

5.50

-

-

8.80

937065^*

94.13

Autosampler stability after 65 h

0.30

0.32

94.12

5.50

-

-

8.80

9.48

97.43

Freeze-thaw cycles (N = 5)

0.30

0.29

96.67

5.50

5.84

106.18

8.80

9.69

110.11

Long term stability (198 day, −80˚C)

0.30

0.29

96.67

5.50

5.57

101.30

8.80

9.14

103.87