Table 1.

Measured and certified values of metal concentrations in standard reference material.

Element	Method Blank (μg/L)	Limit of Detection (μg/L)	Relative Standard Deviation (%)	Measured Value (mg/kg)	Assigned Value (mg/kg)
Cu	1.23	0.04	1.6	27.00 ± 0.60	28 ± 2
Pb	5.47	0.21	2.6	16.40 ± 0.60	23 ± 4
Zn	7.00	1.41	1.2	80.10 ± 1.29	77 ± 6
Cd	0.017	0.009	5.3	0.21 ± 0.015	0.17 ± 0.04
Cr	2.60	0.08	0.9	46.2 ± 0.52	46 ± 8