Abstract
Determination of impurity elements in steel by speak source mass spectrometry using powdered salts sample electrode was studied. The instrument used in this study was an AEI MS-7 mass spectrograph and the ion detector was Ilford Q2 photograph. Sample, (0.51) gram, was dissolved in hydrochloric acid (1:1) or nitric acid (1:1) together with yttrium of 1 microgram as the internal standard and then the solution was evaporated to dryness without baking. The salt residues were dried at 70°C for 30 minutes under vacuum. They were mixed with an equal amount of graphite powder for 5 minutes in a mixer mill, and then pressed into electrodes.
When the relative sensitivity coefficient (Fe =1) was determined by using NBS 460 series standard samples, the results obtained by the proposed method for elements of Mo, Sn, Cu, Cr, Co, Ni, Mn, V, P, Si, and B were in good agreement with those obtained. by the conventional method using solid sample electrodes (the solid method) and the precision of this method for 11 elements mentioned above was about 10% better than those of the solid method. However, both the accuracy and precision for elements of Nb, Ti, S and W were not good. This method was applied to the determination of impurities in NBS stainless steel and others. The relative standard deviations were within 20%.
