Cu

Fe

Cd

Pb

Zn

Ni

Measured value

3.96 ± 0.08

169 ± 4.6

0.78 ± 0.03

1.15 ± 0.04

128 ± 8.00

0.91 ± 0.11

Certified value

4.02 ± 0.33

171 ± 4.9

0.82 ± 0.16

1.19 ± 0.18

137 ± 13.00

0.93 ± 0.12