Sample

Background/(ng/L)

Added/(ng)

Found/(ng/L)

Mean value/(ng/L)

RSD/%

Recovery/%

1＃

0

50.0

38.9~45.2

42.8

9.8

85.6

2＃

16.5

500

386~502

452

7.5

90.4

3＃

38.4

2000

1750~1926

1828

5.8

91.4