Konosuke Oishi

Elemental mass spectrometry using a nitrogen microwave-induced plasma as an ion source

Abstract A new mass spectrometry instrument for trace element analysis was developed that uses a 1.3 kW doughnut-shaped nitrogen high power microwave-induced plasma (MIP-MS). The fundamental analytical features of this doughnut-shaped plasma were studied. Background spectra for distilled water, nitric acid, hydrochloric acid and sulfuric acid, the acids being 1% ( v v ) aqueous solutions, were investigated. In the background spectrum for distilled water, there is no structured peak in the mass range from 49 to 90 amu where most analyte ions are distributed. As a result it is possible to determine K, Ca, Cr, Fe and Se at their major isotopes, which are interfered by polyatomic species in an argon inductively coupled plasma mass spectrometer (ICP-MS). The high power nitrogen MIP-MS exhibited single ppt to sub ppt detection limits for most elements under the multielement scanning condition. However, for the elements As and Se, which have high ionization potentials (> 9.8 eV), the detection limits exhibit high values that are one order of magnitude greater when compared with those of K, Ca and V (

Inverse Zeeman scanning for the measurement of emission line profile in far ultraviolet region

We developed a new technique to observe the profiles of resonance emission lines in UV and VUV regions with a simple apparatus. The radiation from a source passed through an absorption cell placed in a gap of an electromagnet. The wavelength of the absorption line was shifted by means of the inverse Zeeman effect. The emission line profiles were obtained by measuring the absorbance as a function of the magnetic field strength. The emission line profiles and significant self‐reversals were observed for Zn and Cd primary resonance lines at 213.9 and 228.8 nm, respectively.

Development of simultaneous atomic absorption spectrophotometer.

A simultaneous four element atomic absorption spectrophotometer was developed using a graphite furnace sample atomizer and Zeemann background correction method. Four independent gratings were used for the selection of four lines of different wavelengths. Four hollow cathode lamps could be mounted in any combination of elements. Double beam photometry were achieved without cross-talk and spectral interferences by adjacent lines between signal channels. A new temperature program for the graphite furnace was proposed and evaluated experimentally. Detection limits obtained with the proposed spectrophotometer for Se, As, Sb and Pb were, comparable to those of single element AA instruments.