High sensitivity measurement in plasma spectrometry by gas flow modulation technique

气流调制技术在等离子体光谱分析中的高灵敏度测量

• 批准号: 09640713
• 负责人: WAGATSUMA Kazuaki
• 金额: $ 1.92万
• 依托单位: TOHOKU UNIVERSITY
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 1997
• 资助国家: 日本
• 起止时间: 1997 至 1999
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-09640713/
• 关键词: Inductively-coupled atomic emission spectrometry; Glow discharge optical emission spectrometry; Modulation spectroscopy; Detection limit; Plasma gas flow; Bias current; 放電電力変調法

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.

电感耦合等离子体原子发射光谱法（ICP-AES）广泛应用于材料研究的定量分析。为了进一步提高测定限，需要提高信号背景比和信噪比。在电感耦合等离子体原子发射光谱法中，这两个参数都可以通过对发射强度的精确估算得到。调制光谱法适用于此目的，因为只有调制分量可以被检测到以去除任何噪声。在这项工作中，我们提出了一种新的检测系统，ICP-AES通过使用等离子体气体流量调制技术，其中循环引入空气气体到Ar-ICP产生的调制分量的发射信号。该方法的检出限比常规检测方法提高了10倍以上，采用辉光放电发射光谱法（GD-OES）直接测定固体样品。为了改善测量范围，我们在射频辉光放电源中发展了偏置电流调制技术。通过连接低通滤波器电路和负载电阻器可以将直流电流传导到等离子体中，然后可以通过使用开关电路来调制电流，从而产生发射信号的调制分量。与传统的检测方法相比，测定限提高了20-50倍。

项目成果

K.Wagatsuma: "Control of d. c. bias current in radio-frequency glow discharge source and its emission characteristics"Spectrochimica Acta Part B. 54B. 527-535 (1999)

K.Wagatsuma：“射频辉光放电源中直流偏置电流的控制及其发射特性”《光谱化学学报》B.54B 部分。

H. Matsuta and K. Wagatsuma: "Advanced helium glow discharge emission source by conducting d.c. self-bias current in the 13.56 MHz radio frequency plasma"Analytical Sciences. 15. 319-320 (1999)

H. Matsuta 和 K. Wagatsuma：“通过在 13.56 MHz 射频等离子体中传导直流自偏置电流来实现先进的氦辉光放电发射源”分析科学。

K.Wagatsuma: "Selection of self-absorption free analytical lines of aluminum in glow discharge optical emission spectrometry" Analytica Chimica Acta. 343. 267-273 (1997)

K.Wagatsuma：“辉光放电发射光谱法中铝的自吸收自由分析线的选择”Analytica Chimica Acta。

H.Matsuta: "Characteristics of a 40.68-MHz ratio frequency boosted low power glow discharge lamp"Spectrochimica Acta Part B. 54B. 1783-1792 (1999)

H.Matsuta：“40.68 MHz 比率频率升压低功率辉光放电灯的特性”Spectrochimica Acta Part B.54B。

K.Wagatsuma: "Application of a bias current modulation technique to radio-frequency glow discharge optical emission spectrometry"Analytical Sciences. 15. 517-523 (1999)

K.Wagatsuma：“偏置电流调制技术在射频辉光放电发射光谱测定中的应用”分析科学。