Determination of Trace Amounts of Carbon, Nitrogen and Oxygen in Steel by Glow Discharge Mass Spectrometry

Abstract

A glow discharge mass spectrometry (GD/MS) was applied to a quantitative analysis of trace amounts of carbon, nitrogen and oxygen in high purity steel samples. Contaminants on sample surface were main interference for carbon determination. The contaminants can be eliminated succesively by glow discharge in advance of ion intensity measurement. The background can be improved by cooling the glow discharge cell. It was indispensable for nitrogen determination to evacuate the ion chamber for about 20 minutes after a sample was introduced to the system. A background for oxygen determination was improved effectively by purification of Ar gas with zirconium oxide catalyzer. Trace amounts of carbon, nitrogen and oxygen less than 20 ppm in steel were determined quantitatively.