Determination of trace amounts of oxygen, carbon and nitrogen in metals by spark-source mass spectrography

Abstract

To determine trace amounts of oxygen, carbon and nitrogen in iron, nickel and copper by r.f. spark-source mass spectrography, a high-purity GaAs rod was used as one of the sparking electrodes against a sample rod electrode. This GaAs vs. sample electrode method was found effective for the carbon and oxygen analyses, but not for nitrogen analysis. For oxygen contents between 3 and 1000 wt. p.p.m. in iron, nickel and copper, the experimental sensitivity factor lies between 3 and 0.3. For nitrogen in iron and nickel samples, the factor is about 0.5 throughout the whole range of 4 to 900 wt. p.p.m., quite independently of the use of the GaAs electrode. The present method does not require special high-speed pumping, overnight baking or heavy pre-sparking.