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Trace elements in environmental samples determined by X-ray spectroscopy
ARTICLE IN PRESS
Radiation Physics and Chemistry 71 (2004) 801–802
Trace elements in environmental samples determined by X-ray spectroscopy J. Dobrinic´a, N. Orlic´b,*, Z. Kalimanb b
a University of Rijeka, Faculty of Engineering, Vukovarska 58, 51000 Rijeka, Croatia University of Rijeka, Faculty of Philosophy, Department of Physics, Omladinska 14, 51000 Rijeka, Croatia
Trace element concentration was measured in the soil, different kind of oils, and marine organisms. The method of detection of characteristic X-rays was used for simultaneous determination of all biologically essential trace elements. We have used X-ray tube sources, proton beams and mainly radioactive sources to excite the characteristic X-rays from the samples (Valkovic´, 1973). The radiation from a sealed radioactive 109Cd source of 10 mCi is detected in a liquid nitrogen cooled high resolution Si(Li) detector with an active area of 30 mm2, thickness 3 mm. The energy resolution is 170 eV for Fe Ka X-rays. In order to prevent contamination of a detector surface by condensation of impurities, the detector is placed in the vacuum chamber with the beryllium window. The thickness of beryllium window, placed 5 mm in front of the detector, is 5.8 mm. The absorption of X-rays in this window determines the detector efficiency for lower X-ray energies, while the detector size and geometry define the efficiency for high X-ray energies inside the photon energy region 5– 25 keV. In our analyses we have used the K-lines of medium heavy elements and the L-lines of heavy elements from this energy interval. In order to obtain sensitivities for different elements, set of prepared standards (Ca, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Mo, Ba, Ho, Au, Hg, Pb and Bi) were irradiated for 104 s. The resulting number of K- and L-shell X-rays corresponding to 1017 atoms are shown in Fig. 1. This type of specimen excitation was used on targets from samples of soil prepared as powder and deposited on filter membrane. In Table 1 we present the elemental
*Corresponding author. E-mail address: [email protected] (N. Orlic´).
compositions of soil samples. The first sample is taken from the location near a thoroughfare and the other one far from it. Significantly increased concentrations of Pb and Sr are observed in the first sample.
Fig. 1. Number of Ka, and La X-rays produced for 1017 atoms in 104 s for different elements in samples irradiated with a 109Cd radioactive source. The curve for Lb (not shown) corresponds to that for La.
0969-806X/$ - see front matter r 2004 Elsevier Ltd. All rights reserved. doi:10.1016/j.radphyschem.2004.04.099
ARTICLE IN PRESS 802
J. Dobrinic´ et al. / Radiation Physics and Chemistry 71 (2004) 801–802
Table 1 Trace element concentration in soil samples expressed in ppm Element
Sample 1
Sample 2
Fe Zn Pb Br Rb Sr Y Zr
5516 — 258 52 — 238 27 86
31711 86 103 115 185 87 112 566
Sample 1 is taken near the thoroughfare and sample 2 far from a thoroughfare. Errors are of order 710%.
Samples of marine organisms (mussels and cuttlefishes) from different locations in Northern Adriatic sea were dried at 105 and glued on the kapton foil with perspex acetone solution. Absolute concentration of Fe, Zn, As, Br, Sr and Pb were determined using 109Cd excitation (Orlic´ et al., 1979). For the analysis of marine organism the X-ray tube with Mo anode and proton beam from Van der Graaff accelerator were also used. In Table 2 results are presented as the relative concentration to Zn because in the case of protons the absolute concentrations were not measured. Although all three excitation modes produce very similar results, there are differences in the sensitivity and detection limit for particular elements. The proton beam excitation mode shows the highest sensitivities, although it has a remarkable amount of the background induced by the secondary electron bremsstrahlung. Using the X-ray tube, the sensitivities for particular elements can be increased by the proper choice of the fluorescers. In the systems which use radioactive sources the lower
Table 2 Comparison of trace element concentrations relative to Zn for marine organisms Excitation mode
Mn Fe Ni Cu Zn As Br Sr
g-ray source
X-ray tube
Proton beam
0.02970.012 0.07670.011 — 0.08570.013 1 — 0.25070.035 0.02070.003
0.019770.0008 0.09570.003 0.001370.0003 0.12070.003 1 0.004570.0004 0.18370.003 0.02470.001
0.02170.002 0.08770.007 — 0.10970.002 1 — 0.19370.011 0.02270.002
sensitivities can be partly compensated with the use of bigger samples due to the larger solid angles of these systems. Finally, the characteristic X-rays excited by X-rays from Cr-tube and proton beam were used for the determination of trace elements in four different samples of crude oils. Comparably quantities of Ca, S, P, Si and Al are determined in all samples. The concentration of Zn, Cu, Ni, Fe and V varied from sample to sample. Similar results are obtained using radioactive source.
References Orlic´, N., Holjevic´, S., Dobrinic´, J., Ljubicˇic´, A., Valkovic´, V., 1979. X-ray spectroscopy in trace elements analysis in biological specimens. Fizika 11 (1), 69. Valkovic´, V., 1973. X-ray emission spectroscopy. Contem. Phys. 14, 415–439.
Radiation Physics and Chemistry 71 (2004) 801–802
Trace elements in environmental samples determined by X-ray spectroscopy J. Dobrinic´a, N. Orlic´b,*, Z. Kalimanb b
a University of Rijeka, Faculty of Engineering, Vukovarska 58, 51000 Rijeka, Croatia University of Rijeka, Faculty of Philosophy, Department of Physics, Omladinska 14, 51000 Rijeka, Croatia
Trace element concentration was measured in the soil, different kind of oils, and marine organisms. The method of detection of characteristic X-rays was used for simultaneous determination of all biologically essential trace elements. We have used X-ray tube sources, proton beams and mainly radioactive sources to excite the characteristic X-rays from the samples (Valkovic´, 1973). The radiation from a sealed radioactive 109Cd source of 10 mCi is detected in a liquid nitrogen cooled high resolution Si(Li) detector with an active area of 30 mm2, thickness 3 mm. The energy resolution is 170 eV for Fe Ka X-rays. In order to prevent contamination of a detector surface by condensation of impurities, the detector is placed in the vacuum chamber with the beryllium window. The thickness of beryllium window, placed 5 mm in front of the detector, is 5.8 mm. The absorption of X-rays in this window determines the detector efficiency for lower X-ray energies, while the detector size and geometry define the efficiency for high X-ray energies inside the photon energy region 5– 25 keV. In our analyses we have used the K-lines of medium heavy elements and the L-lines of heavy elements from this energy interval. In order to obtain sensitivities for different elements, set of prepared standards (Ca, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Mo, Ba, Ho, Au, Hg, Pb and Bi) were irradiated for 104 s. The resulting number of K- and L-shell X-rays corresponding to 1017 atoms are shown in Fig. 1. This type of specimen excitation was used on targets from samples of soil prepared as powder and deposited on filter membrane. In Table 1 we present the elemental
*Corresponding author. E-mail address: [email protected] (N. Orlic´).
compositions of soil samples. The first sample is taken from the location near a thoroughfare and the other one far from it. Significantly increased concentrations of Pb and Sr are observed in the first sample.
Fig. 1. Number of Ka, and La X-rays produced for 1017 atoms in 104 s for different elements in samples irradiated with a 109Cd radioactive source. The curve for Lb (not shown) corresponds to that for La.
0969-806X/$ - see front matter r 2004 Elsevier Ltd. All rights reserved. doi:10.1016/j.radphyschem.2004.04.099
ARTICLE IN PRESS 802
J. Dobrinic´ et al. / Radiation Physics and Chemistry 71 (2004) 801–802
Table 1 Trace element concentration in soil samples expressed in ppm Element
Sample 1
Sample 2
Fe Zn Pb Br Rb Sr Y Zr
5516 — 258 52 — 238 27 86
31711 86 103 115 185 87 112 566
Sample 1 is taken near the thoroughfare and sample 2 far from a thoroughfare. Errors are of order 710%.
Samples of marine organisms (mussels and cuttlefishes) from different locations in Northern Adriatic sea were dried at 105 and glued on the kapton foil with perspex acetone solution. Absolute concentration of Fe, Zn, As, Br, Sr and Pb were determined using 109Cd excitation (Orlic´ et al., 1979). For the analysis of marine organism the X-ray tube with Mo anode and proton beam from Van der Graaff accelerator were also used. In Table 2 results are presented as the relative concentration to Zn because in the case of protons the absolute concentrations were not measured. Although all three excitation modes produce very similar results, there are differences in the sensitivity and detection limit for particular elements. The proton beam excitation mode shows the highest sensitivities, although it has a remarkable amount of the background induced by the secondary electron bremsstrahlung. Using the X-ray tube, the sensitivities for particular elements can be increased by the proper choice of the fluorescers. In the systems which use radioactive sources the lower
Table 2 Comparison of trace element concentrations relative to Zn for marine organisms Excitation mode
Mn Fe Ni Cu Zn As Br Sr
g-ray source
X-ray tube
Proton beam
0.02970.012 0.07670.011 — 0.08570.013 1 — 0.25070.035 0.02070.003
0.019770.0008 0.09570.003 0.001370.0003 0.12070.003 1 0.004570.0004 0.18370.003 0.02470.001
0.02170.002 0.08770.007 — 0.10970.002 1 — 0.19370.011 0.02270.002
sensitivities can be partly compensated with the use of bigger samples due to the larger solid angles of these systems. Finally, the characteristic X-rays excited by X-rays from Cr-tube and proton beam were used for the determination of trace elements in four different samples of crude oils. Comparably quantities of Ca, S, P, Si and Al are determined in all samples. The concentration of Zn, Cu, Ni, Fe and V varied from sample to sample. Similar results are obtained using radioactive source.
References Orlic´, N., Holjevic´, S., Dobrinic´, J., Ljubicˇic´, A., Valkovic´, V., 1979. X-ray spectroscopy in trace elements analysis in biological specimens. Fizika 11 (1), 69. Valkovic´, V., 1973. X-ray emission spectroscopy. Contem. Phys. 14, 415–439.