Storage condition

Nominal concentration (ng/mL)

Measured concentration (ng/mL)

Recovery (%)

Short term stability (6 h in plasma)

0.30

33,297^*

95.00

5.50

-

-

8.80

1,021,716^*

102.00

Autosampler stability after 65 h

0.30

0.31

96.88

5.50

-

-

8.80

9.11

96.10

Freeze-thaw cycles (N = 5)

0.30

0.28

93.33

5.50

5.94

108.00

8.80

9.01

102.39

Long term stability (198 day, −80˚C)

0.30

0.29

96.39

5.50

5.68

103.20

8.80

9.13

103.78