2006 Volume 92 Issue 6 Pages 406-410
We developed a new He glow-discharge mass spectrometer (He/GD-MS) for ultra trace gas component analysis in iron and steels. To reconstruction of vacuum exhaust system, the turbo-molecular pump, Edwards EXT 555H, was installed on the side of the ion source chamber by modification of the electrodes for ion lens control and the mass flow controller attached to the gas introduction system. Using two standard reference materials of low alloys, we obtained the relative sensitivity factor (RSFO.Fe) of oxygen in the Fe matrix, was 0.450. The analytical results of ultra-low oxygen content of certified reference material, JSAC 0111, showed good agreement with certified value and analytical values obtained by the inert gas carrier impulse furnace fusion/infrared absorption spectrometry. The circadian fluctuation and fluctuation during the day were found to have respective accuracies within approximately 10% in RSD (%). We established a high-precision, high-sensitivity method of quantitatively analyzing an ultra-trace content of oxygen.