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Intelligent simultaneous quantitative online analysis of environmental trace heavy metals with total-reflection X-ray fluorescence.

Ma J, Wang Y, Yang Q, Liu Y, Shi P - Sensors (Basel) (2015)

Bottom Line: Total-reflection X-ray fluorescence (TXRF) has achieved remarkable success with the advantages of simultaneous multi-element analysis capability, decreased background noise, no matrix effects, wide dynamic range, ease of operation, and potential of trace analysis.Besides, spectral overlapping and background effects may lead to loss of accuracy or even faulty results during practical quantitative TXRF analysis.Experimental results verify that simultaneous quantification of trace heavy metals, including Cr, Mn, Fe, Co, Ni, Cu and Zn, is realized on the online TXRF analysis platform, and both high measurement precision and computational efficiency are obtained.

View Article: PubMed Central - PubMed

Affiliation: School of Water Resources & Environment, China University of Geosciences (Beijing), Beijing 100083, China. majunjie85@gmail.com.

ABSTRACT
Total-reflection X-ray fluorescence (TXRF) has achieved remarkable success with the advantages of simultaneous multi-element analysis capability, decreased background noise, no matrix effects, wide dynamic range, ease of operation, and potential of trace analysis. Simultaneous quantitative online analysis of trace heavy metals is urgently required by dynamic environmental monitoring and management, and TXRF has potential in this application domain. However, it calls for an online analysis scheme based on TXRF as well as a robust and rapid quantification method, which have not been well explored yet. Besides, spectral overlapping and background effects may lead to loss of accuracy or even faulty results during practical quantitative TXRF analysis. This paper proposes an intelligent, multi-element quantification method according to the established online TXRF analysis platform. In the intelligent quantification method, collected characteristic curves of all existing elements and a pre-estimated background curve in the whole spectrum scope are used to approximate the measured spectrum. A novel hybrid algorithm, PSO-RBFN-SA, is designed to solve the curve-fitting problem, with offline global optimization and fast online computing. Experimental results verify that simultaneous quantification of trace heavy metals, including Cr, Mn, Fe, Co, Ni, Cu and Zn, is realized on the online TXRF analysis platform, and both high measurement precision and computational efficiency are obtained.

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Typical measured spectrum for multi-element determination, where the Ag-anode X-ray tube is operated at 25 kV and 200 μA, the glancing angle is set as 0.09°, and the counting time of detector is set as 600 s.
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sensors-15-10650-f003: Typical measured spectrum for multi-element determination, where the Ag-anode X-ray tube is operated at 25 kV and 200 μA, the glancing angle is set as 0.09°, and the counting time of detector is set as 600 s.

Mentions: Figure 3 shows a typical measured spectrum, where a number of elements, such as Si, S, K, Ca, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Y, Ag, Hg, and Pb, are recognized. Checking the test condition and atmosphere, we can tell that characteristic peaks of Ag are from the target material of the X-ray tube and characteristic peaks of Si are from the quartz sample carrier. Serious overlapping can be found, such as Mn-Kα against Cr-Kβ, Fe-Kα against Mn-Kβ, Co-Kα against Fe-Kβ, Ni-Kα against Co-Kβ, Cu-Kα against Ni-Kα, Zn-Kα against Cu-Kβ, As-Kα against Pb-Lα, etc. When a specimen contains a number of known and unknown elements, overlapping will be a common phenomenon, and also the real spectral background is hard to determine.


Intelligent simultaneous quantitative online analysis of environmental trace heavy metals with total-reflection X-ray fluorescence.

Ma J, Wang Y, Yang Q, Liu Y, Shi P - Sensors (Basel) (2015)

Typical measured spectrum for multi-element determination, where the Ag-anode X-ray tube is operated at 25 kV and 200 μA, the glancing angle is set as 0.09°, and the counting time of detector is set as 600 s.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4481981&req=5

sensors-15-10650-f003: Typical measured spectrum for multi-element determination, where the Ag-anode X-ray tube is operated at 25 kV and 200 μA, the glancing angle is set as 0.09°, and the counting time of detector is set as 600 s.
Mentions: Figure 3 shows a typical measured spectrum, where a number of elements, such as Si, S, K, Ca, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Y, Ag, Hg, and Pb, are recognized. Checking the test condition and atmosphere, we can tell that characteristic peaks of Ag are from the target material of the X-ray tube and characteristic peaks of Si are from the quartz sample carrier. Serious overlapping can be found, such as Mn-Kα against Cr-Kβ, Fe-Kα against Mn-Kβ, Co-Kα against Fe-Kβ, Ni-Kα against Co-Kβ, Cu-Kα against Ni-Kα, Zn-Kα against Cu-Kβ, As-Kα against Pb-Lα, etc. When a specimen contains a number of known and unknown elements, overlapping will be a common phenomenon, and also the real spectral background is hard to determine.

Bottom Line: Total-reflection X-ray fluorescence (TXRF) has achieved remarkable success with the advantages of simultaneous multi-element analysis capability, decreased background noise, no matrix effects, wide dynamic range, ease of operation, and potential of trace analysis.Besides, spectral overlapping and background effects may lead to loss of accuracy or even faulty results during practical quantitative TXRF analysis.Experimental results verify that simultaneous quantification of trace heavy metals, including Cr, Mn, Fe, Co, Ni, Cu and Zn, is realized on the online TXRF analysis platform, and both high measurement precision and computational efficiency are obtained.

View Article: PubMed Central - PubMed

Affiliation: School of Water Resources & Environment, China University of Geosciences (Beijing), Beijing 100083, China. majunjie85@gmail.com.

ABSTRACT
Total-reflection X-ray fluorescence (TXRF) has achieved remarkable success with the advantages of simultaneous multi-element analysis capability, decreased background noise, no matrix effects, wide dynamic range, ease of operation, and potential of trace analysis. Simultaneous quantitative online analysis of trace heavy metals is urgently required by dynamic environmental monitoring and management, and TXRF has potential in this application domain. However, it calls for an online analysis scheme based on TXRF as well as a robust and rapid quantification method, which have not been well explored yet. Besides, spectral overlapping and background effects may lead to loss of accuracy or even faulty results during practical quantitative TXRF analysis. This paper proposes an intelligent, multi-element quantification method according to the established online TXRF analysis platform. In the intelligent quantification method, collected characteristic curves of all existing elements and a pre-estimated background curve in the whole spectrum scope are used to approximate the measured spectrum. A novel hybrid algorithm, PSO-RBFN-SA, is designed to solve the curve-fitting problem, with offline global optimization and fast online computing. Experimental results verify that simultaneous quantification of trace heavy metals, including Cr, Mn, Fe, Co, Ni, Cu and Zn, is realized on the online TXRF analysis platform, and both high measurement precision and computational efficiency are obtained.

Show MeSH
Related in: MedlinePlus