脉冲熔融-飞行时间质谱法同时测定钨和钽中氧氮氢

Simultaneous determination of oxygen,nitrogen and hydrogen in tungsten and tantalum by pulse heating-time of flight mass spectrometry

在对仪器测定条件优化的基础上,以0.15g镍箔作助熔剂,采用自行设计的由套坩埚和内坩埚组成的新型石墨坩埚,建立了同时测定难熔金属钨、钽中氧、氮和氢的脉冲熔融-飞行时间质谱法。选择与钨、钽产品中氧和氮含量较匹配的钢标准样品建立测定氧和氮的校准曲线,和与钨、钽产品中氢含量较匹配的钛标准样品建立测定氢的校准曲线。方法中氧、氮、氢的检出限分别为0.5μg、0.5μg、0.4μg,测定下限分别为1.7μg、1.7μg、1.2μg。方法用于钨条和钽片样品中氧、氮、氢的测定,对于钨条样品氧、氮、氢测定结果的相对标准偏差分别为5.5%、11.5%、8.9%(n=11),对于钽片样品氧、氮、氢测定结果的相对标准偏差分别为12%、24%、22%(n=11),并且氧、氢和氮的测定结果分别与红外吸收法和热导法基本一致。

Oxygen, nitrogen and hydrogen in refractory metals tungsten and tantalum were simultane- ously determined by the pulse heating-time of flight mass spectrometer under optimal instrument conditions with 0. 15 g 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 hydrogen was established with titanium reference materials with hydrogen that corresponded with tungsten and tantalum products. In this method, the detection limits of oxygen, nitrogen and hydrogen were 0.5 μg,0.5 μg, 0.4 μg, and the limits of quantitation were 1.7 μg, 1.7 μg, 1.2 μg, respectively. The relative standard deviations （RSDs） for the determination of oxygen, nitrogen and hydrogen in tungsten sample were 5.5%, 11.5%, 8.9% （n=11）, while the RSDs for the determination of oxygen, nitrogen and hydrogen in tantalum sample were 12%, 24% and 22% （n= 11）. The determination results of oxygen, nitrogen and hydrogen were basically consistent with those of infrared absorption method and thermoconductivity.