Influence of Digestion Procedure and Residual Carbon on Manganese, Copper, and Zinc Determination in Herbal Matrices by Atomic Absorption Spectrometry

Table 5

Expanded combined uncertainties and relative standard uncertainties for particular contributions calculated for all methods and metal concentrations.

Method	Relative standard uncertainty				Expanded combined uncertainty; µg g^−1
	CRM mass sample	Volumetric flask	Pipette	Standard solutions concentration	Mn	Zn	Cu
Ia	0.0002	0.0016	0.0005	0.002	20.4	4.11	1.11
Ib					15.4	3.34	1.03
Ic					23.1	2.83	1.39
Id					20.6	2.06	1.13
Ie					18.0	2.57	0.77
If					21.2	2.57	1.08
Ig					23.1	2.31	0.67
II	0.0002	0.0012	0.0005	0.002	15.4	5.40	1.23
III	0.0001				28.3	4.37	1.29
IV					18.0	3.60	1.54
V					18.0	2.83	0.95
VI	0.0002	0.0016	0.0005	0.002	18.0	3.86	1.16
VII		0.0012			23.1	2.83	0.77
VIII	0.0001				23.1	2.83	1.29
IX	0.00005	0.001			25.7	2.31	1.00

Pipette volume = 10 mL; concentrations of all Mn, Zn, and Cu standard solutions were c = 1.0000 mg L⁻¹.