Rapid simultaneous multi-element determination of soils and environmental samples with polarizing energy dispersive X-ray fluorescence (EDXRF) spectrometry using pressed powder pellets

Figures & data

Table 1 Standard reference materials used for calibration

Name	Basic information	Producer
JA-1	Andesite (1982), Hakone volcano, Quaterary, Kanagawa, Japan	GSJ
JA-2	Andesite (1985), Goshikidai sanukitoid, Sakaide, Kagawa, Japan	GSJ
JA-3	Andesite (1986), Asama volcano, Tsumagoi, Gunma, Japan	GSJ
JB-1a	Basalt (1984), Kitamatsuura basalt, Sasebo, Nagasaki, Japan	GSJ
JB-2	Basalt (1982), Oshima volcano erupted in 1950–1951, Oshima, Tokyo, Japan	GSJ
JB-3	Basalt (1983), Fuji volcano, Narusawa, Yamanashi, Japan	GSJ
JF-2	Feldspar (1986), Kurosaka feldspar, Kurosaka, Ibaraki, Japan	GSJ
JGb-1	Gabbro (1983), Utsushigatake, Funehiki, Fukushima, Japan	GSJ
JGb-2	Gabbro (1991), Tsukuba-san leucogabbro, Yasato, Ibaraki, Japan	GSJ
JR-1	Rhyolite (1982), Wada Toge obsidian, Wada, Nagano, Japan	GSJ
JR-2	Rhyolite (1983), Wada Toge obsidian, Shimosuwa, Nagano, Japan	GSJ
JR-3	Rhyolite (1990), Ashizuri peralkaline rhyolite, Tosashimizu, Kochi, Japan	GSJ
JLk-1	Lake sediment (1987), Lake Biwa, Shiga, Japan	GSJ
JSd-1	Stream sediment (1988), Northern region, Ibaraki, Japan	GSJ
JSd-2	Stream sediment (1989), Eastern region, Ibaraki, Japan	GSJ
JSd-3	Stream sediment (1989), Central region, Ibaraki, Japan	GSJ
JS1-1	Slate (1988), Toyoma clay slate, Toyama, Miyagi, Japan	GSJ
JS1-2	Slate (1989), Toyoma clay slate, Okatsu, Miyagi, Japan	GSJ
SO-1	Regosolic clay soil, Hull, Quebec, Canada	CCRMP
SO-2	Podzalic B horizon soil, Montmorency forest, Quebec City, Canada	CCRMP
SO-3	Calcareous C horizon soil, Guelph, Ontario, Canada	CCRMP
SO-4	Chemozemic A horizon soil, Saskatoon, Saskachewan, Canada	CCRMP
NIST 2704	Buffalo River Sediment (reference material 8704)	NIST
NIST 2709	San Joaquin soil (baseline trace element concentrations)	NIST
NIST 2710	Montana soil (highly elevated trace element concentrations)	NIST
NIST 2711	Montana soil (moderately elevated trace element concentrations)	NIST
CCRMP, Canadian Certified Reference Materials Project; GSJ, Geological Survey of Japan; NIST, National Institute of Standards and Technology, USA.

Table 2 Measurement conditions for the major constituents

Analytes	X-ray tube		Secondary target	Measurement time (min)^†	Matrix correction procedure
	Voltage (kV)	Current (mA)
Na2O, MgO	25	24	Al	40	FP
A12O3∼K2O	40	15	CaF2	10	FP
CaO, TiO2	75	8	Fe	5	FP
MnO, Fe2O3	75	8	Ge	5	FP
^†Real time. FP, fundamental parameter method.

Table 3 Measurement conditions for the trace elements

Analytes	X-ray tube		Secondary target	Measurement time (min)^†	Matrix correction procedure^‡
	Voltage (kV)	Current (mA)
V	75	8	Fe	5	Fe-C
Cr∼Zn	75	8	Ge	10	Ge-C
Rb∼Y	100	6	Mo	10	Mo-C
Zr∼Nd	100	6	A12O3 ^§	10	Ce-C
Pb, Th	100	6	Mo	10	Mo-C
^†Real time. ^‡Compton scattering method. ^§Barkla scatter.

Table 4 Analytes and analytical lines for inductively coupled plasma-atomic emission spectrometry

Analyte	Ionization state	Analytical line (nm)
Na2O	I	588.995
MgO	I	285.213
A12O3	I	396.152
K2O	I	766.491
CaO	I	422.694
TiO2	II	334.941
V	II	292.401
MnO	II	257.610
Fe2O3	II	238.204
Sr	II	407.701
Ba	II	455.403
I, neutral line; II, singly ionized line.

Table 5 Analytical figures of merit for the major constituent calibrations

Analyte	N	Range (wt %)	R	RMSE (wt %)
Na2O	23	0.41–4.69	0.9660	0.30
MgO	22	0.01–8.42	0.9527	0.88
Al2O3	23	5.80–23.5	0.9395	1.28
SiO2	23	33.7–75.7	0.9738	2.49
P2O5	19	0.003–0.294	0.9475	0.03
K2O	23	0.06–12.9	0.9989	0.15
CaO	22	0.09–9.82	0.9996	0.12
TiO2	23	0.010–1.600	0.9914	0.06
MnO	23	0.001–0.266	0.9970	0.005
Fe2O3	23	0.06–15.1	0.9967	0.35
N, number of reference materials used for the calculation; R, correlation coefficient of the linear regression lines; RMSE, root mean square error. RMSE = (Σ (Xa − Xb)^2/(N − 2))^1/2, where Xa is the content in the reference material, Xb is the content calculated using the regression equation and N is the number of reference materials.

Table 6 Analytical figures of merit for the trace element calibrations

Analyte	N	Range (mg kg^−1)	R	RMSE (mg kg^−1)
V	25	3–635	0.9851	28
Cr	26	2.47–436	0.9929	13
Co	26	0.46–60.1	0.8940	7.2
Ni	26	1.38–139	0.9928	4.8
Cu	23	0.78–426	0.9987	5.1
Zn	24	1.4–408	0.9962	8.2
Rb	25	2.9–453	0.9985	6.2
Sr	24	8.11–442	0.9991	5.6
Y	22	2.67–51.1	0.9905	4.3
Zr	22	6.73–270	0.9977	21
Nb	17	0.7–26.9	0.9801	1.5
Sn	16	0.13–32.5	0.9966	0.7
Sb	21	0.04–38.4	0.9928	1.1
Cs	20	0.26–30.6	0.9958	0.8
Ba	26	36.5–1199	0.9970	25
La	24	0.63–54.0	0.9877	2.4
Ce	25	0.84–112	0.9944	3.2
Pr	21	0.083–14.3	0.8386	2.0
Nd	22	0.33–57.0	0 9621	3.8
Pb	23	1.5–150	0.9900	5.9
Th	16	0.19–31.4	0.9892	1.5
N, number of reference materials used for the calculation; R, correlation coefficient of the linear regression lines. RMSE, root mean square error. RMSE = (Σ (Xa − Xb)^2/(N − 2))^1/2, where Xa is the content in the reference material, Xb is the content calculated using the regression equation and N is the number of reference materials.

Table 7 Instrument stability of the major constituents†

Analyte	Content (weight %)	RSD of X-ray intensity (%)	X-ray intensity per unit wt% (CPS/wt %)
Na2O	1.05	2.18	2.71
MgO	1.74	0.51	13.5
Al2O3	16.73	0.23	33.0
SiO2	57.16	0.09	54.1
P2O5	0.208	4.66	45.7
K2O	2.81	0.07	1595
CaO	0.686	0.26	752
TiO2	0.668	0.21	1379
MnO	0.266	0.36	2061
Fe2O3	6.93	0.06	2778
^†Sample: JLk-1; number of repetitions: 24. CPS, counts per second; RSD, relative standard deviation.

Table 8 Instrument stability of the trace elements†

Analyte	Concentration (mg kg^−l)	RSD of X-ray intensity (%)
V	1254	0.265
Cr	1058	0.280
Co	1022	0.150
Ni	1002	0.237
Cu	1176	0.256
Zn	1084	0.163
As	1004	0.167
Sr	79	0.516
Y	1028	0.105
Zr	1061	0.181
Cd	104	0.301
Sn	101	0.417
Sb	99	0.363
Ba	327	0.277
W	100	0.480
Pb	1012	0.223
Bi	101	0.531
^†Sample: JSO-2; number of repetitions: 24. RSD, relative standard deviation.

Table 9 Results of the linear regression analysis

Analyte	Linear regression equation^†		Concentration of the samples (mg kg^−1)
	R	Slope	Range	Median
Group 1 (R > 0.98)
Sr	0.9950	0.9855	12–669	155
Ni	0.9923	1.1053	2–145	19
MnO	0.9896	1.0266	0.004–0.55^‡	0.09^‡
TiO2	0.9877	0.9828	0.12–2.46^‡	0.75^‡
Cs	0.9866	0.9798	0.5–20.2	4.4
Rb	0.9864	1.0977	7–133	51
Ba	0.9861	0.9941	37–740	383
Fe2O3	0.9841	1.0429	1.1–13.9^‡	6.3^‡
CaO	0.9839	1.0017	0.03–6.10^‡	1.6^‡
Ce	0.9819	1.0659	5–129	44
Zn	0.9813	1.0531	21–361	97
K2O	0.9811	1.0638	0.25–2.75^‡	1.51^‡
Group 2 (0.98 R > 0.92)
Al2O3	0.9787	0.9976	5.1–33.6^‡	18.2^‡
Nd	0.9757	1.0521	3.8–77.1	19.5
P2O5	0.9754	1.0583	0.09–0.48^‡	0.20^‡
SiO2	0.9751	0.9626	23.2–84.7^‡	57.7^‡
Cr	0.9734	1.4046	2–200	40
Cu	0.9723	1.0700	3–114	23
La	0.9718	1.1691	2.8–63	19.8
Th	0.9700	0.9320	0.9–21.8	5.9
Y	0.9688	1.2613	8.1–161	27
V	0.9546	1.1481	16–291	100
Nb	0.9512	1.1309	1.1–30.6	8.0
Pb	0.9248	1.0274	4.1–60.8	20.1
Group 3 (R < 0.92)
MgO	0.9134	1.3678	0.26–2.41^‡	1.05^‡
Pr	0.9016	0.9713	0.9–17.6	4.9
Sn	0.8932	2.0676	0.37–6.38	1.81
Sb	0.8130	0.9573	0.21–6.41	0.96
Na2O	0.7915	0.7556	0.02–3.53§	1.35§
Co	0.6059	1.4598	0.6–34	11.2
Zr	0.3977	1.7093	7–249	87
^†Linear regression equation was calculated in such a way as to force the equation to cross the Y-axis (energy dispersive X-ray fluorescence value) at zero when the X values (chemical results) are zero; ^‡Weight (%). R, correlation coefficient.

Figure 1 Energy dispersive X-ray fluorescence concentration data plotted against the values obtained by inductively coupled plasma-mass spectrometry or inductively coupled plasma-atomic emission spectrometry. The superimposed line of slope = 1.0 does not represent a line of “best fit”.