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Production of Microwave-Induced Helium Plasma at Atmospheric-Pressure and Its Application to Mass Spectrometry for Trace Element Analysis

大气压下微波诱导氦等离子体的产生及其在微量元素分析质谱中的应用

基本信息

批准号：
05650817
负责人：
OKAMOTO Yukio
金额：
$ 1.47万
依托单位：
Toyo University
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1993
资助国家：
日本
起止时间：
1993 至 1994
项目状态：
已结题

项目摘要

A high power (1.5 kW,2.45 GHz) atmospheric pressure helium microwave-induced plasma for trace elemnt analysis was produced using a Okamoto cavity (J.Anal.At.Spectrom., 7 (1991) 283-289) operated in a surface wave mode. The fundamental analytical features of the plasma (annular-shaped) ware examined by measuring the emission and mass intensities.The cavity, nonresonant and with no cooling, consists of two parts. One section is a reduced flat rectangular waveguide (thickness : 6.4 mm, width : 109.2 mm). The other section is a mode transfer which consists of an inner conductor and an outer cylindrical conductor terminated by a front plate. The distance between the front plate and the front edge of the inner conductor, gap, is 5 to 10 mm. The surface wave is excited in the gap.Spatial profiles of the emission spectra for helium obtained from 200 to 850 nm. Emissions from the helium plasma were He I (587.6 nm, 23.0 eV), He I (388.9 nm, 23.0 eV) and He I (667.8 nm, 23.1 eV) et al. The domina … More nt peak was He I (587.6 nm) Weak background peaks obtained for OH (306.4 nm, 4.1 eV) and O I (777.6 nm, 10.7 eV).Gas sample (100 ppm) ; argon (Ar, ionization potential : 15.8 eV) or nitrogen (N_2,15.5 eV) introduced into the helium plasma and Ar I (811.5 nm) or N I (746.8nm) emission could be detected. The plasma is a sesitive ionization source.Solution sample (Fe : 1000 ppm) was introduced into the plasma through the inner tube using an ultra sonic nebulizer without a desolvation system (laboratory built). Using a pneumatic nebulizer of an Ar ICP,the plasma became unstable.The Fe I excitation temperatue was obtained from the Boltzmann plot of emission intensities vesus the energy of the upper state in the transition. The excitation temperature of 5500 K was obtained and electron density of 10^<14>/cm^3 was calculated at the microwave power of 1kW.These values show that the plasma is the most useful excitation and/or ionization source for trace element analysis.More details of this work and its application for mass spectrometry are currently being investigated in our laboratory and willbe published in the near feature. Less

使用Okamoto腔产生用于痕量元素分析的高功率（1.5kW，2.45GHz）大气压氦微波诱导等离子体（J.Anal.At.Spectrom.，7（1991）283-289）以表面波模式操作。等离子体（环形）的基本分析特征是通过测量发射和质量强度来检验的。一部分是缩小的扁平矩形波导（厚度：6.4mm，宽度：109.2mm）。另一部分是模式转换，它由一个内导体和一个外圆柱形导体由前板终止。前板与内导体前缘之间的距离为5 ~ 10 mm，在差距中激发表面波，获得了氦原子发射光谱在200 ~ 850 nm的空间分布。氦等离子体的发射为He I（587.6nm，23.0eV）、He I（388.9nm，23.0eV）和He I（667.8nm，23.1eV）等。 ...更多信息 NT峰值为He I（587.6 nm）OH的弱背景峰（306.4 nm，4.1 eV）和O I气体样品（100 ppm）;氩气（Ar，电离势：15.8eV）或氮（N_2，15.5eV）引入到氦等离子体中，可检测到Ar I（811.5nm）或N I（746.8nm）的发射。等离子体是一个敏感的电离源。溶液样品（Fe：1000 ppm）通过内管使用超声雾化器引入等离子体中，没有去溶剂化系统（实验室建造）。用Ar ICP的气动雾化器使等离子体变得不稳定，由发射强度与跃迁中上能级能量的Boltzmann图求得Fe I的激发温度。在微波功率为1 kW时，等离子体的激发温度为5500 K，电子密度为10^<14>/cm ^3，表明等离子体是痕量元素分析中最有用的激发源和电离源。本实验室目前正在进一步研究这项工作及其在质谱中的应用，并将在近期发表。少