Determination of 13 Trace Elements in High Purity Tungsten Powder by Inductively Coupled Plasma Mass Spectrometry

The high purity tungsten powder sample （0.500 0 g） was taken and placed in a polytetrafluoroethylene beaker, and 4 mL of 50% （volume fraction） nitric acid solution and 5 mL of hydrofluoric acid were added. The mixture was heated on an electric hot plate at 90 ℃ to dissolve, and then cooled to room temperature. The solution was transferred to a 100 mL-plastic volumetric flask, made its volume up to 100 mL with water, and mixed well. 5 mL of the solution was taken, and 1 mL of hydrofluoric acid was added. The solution was made its volume up to 50 mL with water and mixed well, and 13 trace elements in the solution were determined by inductively coupled plasma mass spectrometry. Magnesium and aluminum were determined in standard mode, while chromium, manganese, iron, cobalt, copper, nickel, arsenic, molybdenum, tin, antimony, and lead were determined in kinetic energy discrimination collision mode. Matrix interference was reduced by the standard addition method combined with online internal standard addition method. As shown by the results, linear relationships between the ratios of the corresponding signal intensity to the internal standard signal intensity and mass concentrations of the 13 target elements were kept in definite ranges, with detection limits （3s） in the range of 0.01−0.30 µg·g⁻¹. RSDs （n=6） of the determined values of actual high purity tungsten powder samples were less than 10%. Test for recovery was made according to the standard addition method, giving results in the range of 92.0%−106%. The method was applied to the analysis of an actual high purity tungsten powder sample, and the determined values of target elements were basically consistent with those obtained by glow discharge mass spectrometry.