AL nominal conc. (ngmL-1)

40

400

4000

Room temperature (4 h)
Measured conc. (ngmL-1)
Accuracy (%)

43±4

380±15

3799±129

108±11

95±4

95±3

Three freeze/thaw cycles
Measured conc. (ngmL-1)
Accuracy (%)

42±6

424±26

3735±129

104±14

106±7

93±3

Autosampler rack for 24 h
Measured conc. (ngmL-1)
Accuracy (%)

39±1

377±42

4028±180

97±3

94±11

101±5

Stored at -20℃for 1month
Measured conc. (ngmL-1)
Accuracy (%)

40±5

393±20

3652±124

99±14

98±5

91±3