Concentration (μg/mL)

Measured (mg/L, Mean ± S.D., n = 5)

C.V. (%)

Recovery (%)

Intra-day assay

1.25

1.17 ± 0.09

7.7

93.6

5

4.67 ± 0.26

5.6

93.4

40

42.5 ± 2.2

5.2

106.3

Inter-day assay

1.25

1.13 ± 0.10

8.8

90.4

5

4.64 ± 0.33

7.1

92.8

40

41.6 ± 2.6

6.3

104.0