Table 7.

Procedural blanks, limits of detection (LOD) and the results for trace elements measured in CASS-4 and SLEW-3 with optimized Mg(OH)₂ coprecipitation procedure. Values are for mean ± standard deviation of five replicate measurements (n = 5)

Element/ Isotope	Blank (µg L−1)	LOD (µg L−1)	CASS-4 (µg L−1)			SLEW-3 (µg L−1)
			Measured	Certified	%RSD	Measured	Certified	%RSD
27Al	0.22	0.072	3.11 ± 0.25	NR	8.0	2.28 ± 0.20	NR	8.8
51V	0.014	0.006	1.08 ± 0.05	1.18 ± 0.16	4.6	2.59 ± 0.20	2.57 ± 0.31	7.7
52Cr	0.025	0.011	0.162 ± 0.025	0.144 ± 0.029	15	0.198 ± 0.031	0.183 ± 0.019	16
55Mn	0.015	0.004	2.59 ± 0.14	2.78 ± 0.19	5.4	1.47 ± 0.12	1.61 ± 0.22	8.2
56Fe	0.204	0.033	0.732± 0.071	0.713 ± 0.058	9.6	0.644 ±0.026	0.568 ± 0.059	4.1
56Fea			0.718± 0.056		7.8	0.582 ±0.03		5.1
59Co	0.003	0.0006	0.026 ± 0.003	0.026 ± 0.003	11	0.039 ± 0.006	0.042 ± 0.010	15
60Ni	0.065	0.016	0.306 ± 0.034	0.314 ± 0.030	11	1.12 ± 0.082	1.23 ± 0.07	7.3
63Cu	0.070	0.024	0.642 ± 0.045	0.592 ± 0.055	7.0	1.35 ± 0.15	1.55 ± 0.12	11
68Zn	0.125	0.045	0.420 ± 0.12	0.381 ± 0.057	28	0.256 ± 0.035	0.210 ± 0.037	13
68Zna			0.405 ± 0.06		15	0.234 ± 0.02		8.5
69Ga	0.004	0.0003	BDL	NR		BDL	NR
75As	0.006	0.004	0.987 ± 0.14	1.11 ± 0.16	14	1.22 ± 0.08	1.36 ± 0.09	6.5
82Se	0.014	0.008	0.053 + 0.004	NR	7.5	0.044 ± 0.008	NR	18
112Cd	0.002	0.0003	0.029 ± 0.004	0.026 ± 0.003	14	0.043 ± 0.004	0.048 ± 0.004	9.3
120Sn	0.032	0.006	0.032 ± 0.008	NR	25	0.043 ± 0.008	NR	18
120Sna			0.036 ± 0.004		11	0.048 ± 0.005		10
121Sb	0.017	0.005	0.126 ± 0.012	NR	9.5	0.148 ± 0.015	NR	10
208Pb	0.062	0.008	0.015 ± 0.010	0.0098 ± 0.0036	66	0.013 ± 0.008	0.0090 ± 0.0014	61
208Pba			0.013 ± 0.0028		22	0.012 ± 0.003		25

^aResults obtained for CASS-4 and SLEW-3 spiked with 0.05 µg L⁻¹ Pb, Sn, and 0.5 µg L⁻¹ Fe, Zn.

NR: not reported.

BDL: below detection limit.