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

Table 3

Metal contents, recoveries, and nonpurgeable organic carbon (NPOC) in certified reference materials containing herbs. All values are accompanied by standard uncertainties. Digestion in the closed microwave system (Ia–Ig); wet digestion in the open system (II–VI); and dry ashing in the open system (VII–IX) followed by the FAAS were applied. Metal concentrations reported for CRM were Mn = 191 ± 12 µg g⁻¹; Zn = 33.5 ± 2.1 µg g⁻¹; Cu = 7.77 ± 0.53 µg g⁻¹.

Method	Metal (µg g^−1)						NPOC; mg L^−1
	Mn	Recovery%	Zn	Recovery%	Cu	Recovery%
Ia	179 ± 8	94 ± 4	29.5 ± 1.6	88 ± 5	7.24 ± 0.43	93 ± 5	258 ± 2
Ib	180 ± 6	94 ± 3	29,1 ± 1.3	87 ± 4	7.66 ± 0.40	99 ± 5	94.0 ± 1.5
Ic	179 ± 9	94 ± 5	27.7 ± 1.1	83 ± 3	7.17 ± 0.54	92 ± 7	91.0 ± 1.0
Id	178 ± 8	93 ± 4	28.1 ± 0.8	84 ± 2	7.59 ± 0.44	98 ± 6	84.3 ± 0.8
Ie	181 ± 7	95 ± 4	29.6 ± 1.0	88 ± 3	7.74 ± 0.30	99 ± 4	391 ± 4
If	196 ± 8	103 ± 4	30.0 ± 1.0	90 ± 3	7.82 ± 0.42	101 ± 5	1012 ± 11
Ig	196 ± 9	103 ± 5	29.7± 0.9	89 ± 3	7.98 ± 0.26	103 ± 3	745 ± 7
II	186 ± 6	97 ± 3	26.6 ± 2,1	79 ± 6	7.05 ± 0.48	91 ± 6	275 ± 2
III	197 ± 11	103 ± 6	32.2 ± 1.7	96 ± 5	7.21 ± 0.50	93 ± 6	3140 ± 22
IV	201 ± 7	105 ± 4	30.3 ± 1.4	90 ± 4	7.55 ± 0.60	97 ± 8	1857 ± 13
V	186 ± 7	97 ± 4	30.2 ± 1.1	90 ± 3	7.94 ± 0.37	102 ± 5	558 ± 2
VI	164 ± 7	86 ± 4	26.2 ± 1.5	78 ± 4	7.61 ± 0.45	98 ± 6	3300 ± 22
VII	190 ± 9	100 ± 5	34.4 ± 1.1	103 ± 3	7.93 ± 0.30	102 ± 4	5.62 ± 0.11
VIII	192 ± 9	101 ± 5	40.5 ± 1.1	121 ± 3	9.64 ± 0.50	124 ± 6	10.5 ± 0.2
IX	166 ± 10	87 ± 5	35.2 ± 0.9	105 ± 3	7.68 ± 0.39	99 ± 5	6.25 ± 0.12