Improvement of Sentivity and Speed of the Determination of Trace Elements by High Power Microwave Induced Plasma Atomic Emission Spectrometry

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This project has been performed over the last three years to establish a new system of high-power micro-wave-induced plasma (MIP)-atomic emission spectrometry (AES) and to improve the sensitivity and speed of MIP-AES determination of trace elements. The results are as follows.1.In this work, a new system of high-power MIP-AES has been designed and constructed as such an instrument is not available in the marketplace. It consists of a new type of resonant cavity and a computer-controlled spectrometer system for the multi-element determination. For the improvement of response time, the electronic circuit in the computing system was replaced with a rapidly working one.2.In contrast with a common low-power MIP, this high-power nitrogen N/HP can have a great tolerance to continuous nebulization of sample solutions. Furthermore, the constructed system has been modified to combine this MIP with a hydride generation technique as a highly efficient sample introduction.3.With the use of this new … More ly constructed MIP-AES system coupled with a conventional solution nebulization, background emission spectra have been measured. As a result, some typical molecular band emissions were observed in the spectral range of 200-400 nm. In addition, analytical characteristics of this high-power nitrogen MIP were examined at many emission lines of a number of elements.4.For the sensitive determination of arsenic, antimony and selenium, their gaseous hydrides generated by the reaction with sodium tetrahydroborate were continuously conveyed into the MIP with no trouble. The hyphenated method has been successfully applied to the determination of arsenic, antimony or selenium in copper metals and steels with satisfactory results. Furthermore, the simultaneous multi-element determination system was developed and it application to steel analysis has been very successful.5.For a future prospect of this project, a newly developed high-power nitrogen MIP-AES system should be more and more examined and applied to the much wider range of practical samples. If this system can be coupled with other analytical techniques, chemical speciation might be possible and useful, for example, in environmental chemistry. In addition, this technique can be extended to a great extent by the use of a number of sample introduction methods, i.e., ultrasonic nebulization, electrothermal vaporization, slurry sample introduction, laser ablation, spark & arc sampling and glow discharge. Less