Tantalum metal is analyzed for 12 impurity elements by using a carrier distillation technique with a dc arc. The metal is oxidized in a muffle oven at 900°C. The oxide is mixed with a special carrier made of silver metal, silver chloride, and barium fluoride. A set of standards is included on each plate, and the analytical curves are linear for the concentration range used. The coefficient of variation varies from 3 0 to 8 7%.
Roger D. Laib, "Spectrographic Analysis of Tantalum and Tantalum Oxide," Appl. Spectrosc. 17, 160-163 (1963)