Trial Design and Construction of High Power Microwave - Induced Plasma Atomic Emission Spectrometry System

1991 Fiscal Year Final Research Report Summary

• Project/Area Number: 02557028
• Research Category: Grant-in-Aid for Developmental Scientific Research (B)
• Allocation Type: Single-year Grants
• Research Field: Hygiene
• Research Institution: Iwate Medical University
• Principal Investigator: TSUNODA Humio Iwate Medical University, Hygiene & Pub. Health, Professor, 医学部・衛生学公衆衛生学講座, 教授 (80048256)
• Co-Investigator(Kenkyū-buntansha): NAKAYA Shigenao Iwate Medical University, Hygiene & Pub. Health, Lecturer, 医学部・衛生学公衆衛生学講座, 講師 (70048552) ; ITAI Kazuyoshi Iwate Medical University, Hygiene & Pub. health, Assistant, 医学部・衛生学公衆衛生学講座, 助手 (10048572)
• Project Period (FY): 1990 – 1991
• Keywords: He-MIP / N_2-MIP / Atomic emission spectrometry / Trace element / Sequential multielement analysis / Biological materials

Research Abstract

A microwave-induced plasma system can produce a helium plasma. The helium plasma(HE-MIP)will become a powerful source of excitation, enabling the determination of all elements. The aim of this project was the design and construction of the system of HE-MIP atomic emission spectrometry and the study of the application.
The system was constructed from a microwave generator(3kW maximum power), rectangular waveguides, a EH tuner and a cavity. To produce and sustain a stable plasma, the design and construction of a cavity and a discharge tube were very important. First, thecavitydesignedbyBeenakkerwasutilized. Butahighpower(IkW)ofmicrowavecouldnotbeintroduced to the cavity and it was also impossible to match the impedance. Iii tlie result, we manufactured tlie same cavity as Okwnoto manufactured. This cavity can produce and sustain a stable plasma for several hours without heating.
With this cavity, to produce and sustain a stable helium plasma for several hours, tlie discharge tubes were pre pared alumina and zirconium oxide tubes, but these tubes were immediately destroyed. When we produce a helium plasma with the same discharge tube as that used in tlie ordinary ICP system, the plasma considerably tended to localize in the tube, and the plasma was in contact with the wall of the tube and the tube was nielted. Next, we prepared the discharge tube with three tubes in a tube. Nitrogen was used as a most outer gas to prevent the plasi-na froin being in contact with the wall and the flow rate was 10 - 151/min. Though the plasma was not contact with tlie wall, as the plasma mixed with helium and nitrogen was produced, the atomic emission of fluorine was not observed.
While it was impossible to prepare He-MIP system for the determination of all elements, the stable plasma consisted of only nitrogen gas was able to be produced and sustained for several hours. Sequential multielement analysis of some trace elements in biological materials with the N2-MIP system was studied. In feature, to determine halogen such as fluorine by HeMIP system, the plasma consisted of only helium gas must be produced by making the suitable discharge tube.