1999 Fiscal Year Final Research Report Summary
High sensitivity measurement in plasma spectrometry by gas flow modulation technique
| Project/Area Number |
09640713
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
分離・精製・検出法
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| Research Institution | TOHOKU UNIVERSITY |
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Principal Investigator |
WAGATSUMA Kazuaki Institute for Materials Research, Tohoku University, Associate Professor, 金属材料研究所, 助教授 (30158597)
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| Co-Investigator(Kenkyū-buntansha) |
MATSUTA Hideyuki Institute for Materials Research, Tohoku University, Research Associate, 金属材料研究所, 助手 (00181735)
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| Project Period (FY) |
1997 – 1999
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| Keywords | Inductively-coupled atomic emission spectrometry / Glow discharge optical emission spectrometry / Modulation spectroscopy / Detection limit / Plasma gas flow / Bias current |
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| Research Abstract |
ICP-AES (inductively-coupled plasma atomic emission spectrometry) is extensively applied to quantitative analysis for materials research. To improve the determination limits further, increases in the signal-to-background ratio as well as the signal-to-noise ratio are necessary. In ICP-AES, both of them can be obtained from accurate estimation in the emission intensities. Modulation spectroscopy is suitable for this purpose, because only the modulated component can be detected to remove any noises. In this work, we suggest a new detection system for ICP-AES by using a plasma gas flow modulation technique in which cyclic introduction of air gas into the Ar-ICP produces the modulated component of the emission signals. The determination limits are improved by a factor of 10 or more compared to that in the conventional detection method.
GD-OES (glow discharge optical emission spectrometry) is employed for direct determination of solid samples. To better the determination limits, we develop the bias-current modulation technique in the radio-frequency glow discharge source. D.c. currents can be conducted into the plasma by connecting a low-pass filter circuit and a load resister and then the currents can be modulated by using a switching circuit, leading to the modulated component of the emission signals. The determination limits are improved by a factor of 20-50 compared to those in the conventional detection method.
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