Oxygen,nitrogen and hydrogen in refractory metals tungsten and tantalum were simultaneously determined by the pulse heating-time of flight mass spectrometer under optimal instrument conditions with 0.15g of nickel foil as flux agent and self-designed graphite crucible which consists of outer and inner crucibles.The calibration curves of oxygen and nitrogen were established with steel reference materials with oxygen and nitrogen that corresponded with tungsten and tantalum products.The calibration curve of h...