Stability

Spiked conc

(ng∙mL−1)

Calculated comparison sample

concentration (ng∙mL−1)d

Calculated stability sample

concentration (ng∙mL−1)d

Avg%

Mean ± SD

% CV

Mean ± SD

% CV

Bench topa

15

14.89 ± 0.09

3.8

14.86 ± 0.15

8.5

98

4750

4742.6 ± 48.5

2.5

4738.2 ± 84.3

3.2

98.5

9500

9484.7 ± 103.4

2.1

9435.3 ± 122.4

1.3

100

Freeze and thawb

15

14.94 ± 0.1

5.8

14.82 ± 0.2

8.4

96.4

4750

4746.4 ± 86.3

2.7

4743.8 ± 57.8

3.1

98.9

9500

9503.7 ± 104.4

1.9

9498.2 ± 121.3

1.5

100

Long termc

15

14.88 ± 0.1

4.2

14.79 ± 0.14

5.2

97

4750

4748.5 ± 72.6

2.4

4745.3 ± 62.3

3.0

99

9500

9451.6 ± 113.4

2.6

9448.2 ± 97.6

1.7

99.5