抗坏血酸辅助-GFAAS法测定含铁镍基高温合金中痕量镓

Determination of trace gallium in iron-bearing nickel-base alloys by ascorbic acid assisted-graphite furnace atomic absorption spectrometry

采用王水和HF溶解样品,应用GFAAS法直接测定镍基高温合金中痕量Ga。分别探讨了含Fe和不含Fe样品中Ga的测定条件,以及不同含Fe量对Ga的影响。通过抗坏血酸辅助来还原Fe3+,以消除Fe的干扰,同时起到基体改进剂的作用。在选择灰化和原子化温度时,不能单纯的考虑吸收值的大小,而应当综合考虑峰的形状以及信背比大小等因素来确定。采用峰高测量方式,标准加入法进行测定。含铁样品中6~25μg/L Ga的回收率在91%~107%之间,相对标准偏差为15%。可以满足科研和生产的需求。

This paper focused on the direct determination of trace gallium in nickel-base alloys by GFAAS. The sample was dissolved by aqua regia and HF acid. The effects of vary iron concentration on Ga analysis in nickel-base alloys were discussed. Ascorbic acid was chosen as matrix modifier and applied to eliminate the interference from Fe by reduction of Fe^3＋. Not only the absorbing value but also the peak-shape and the ratio of signal to background must be considered when optimizing with ashing or atomization temperature. The peaking combined with standard-adding was applied here. The recoveries of Ga were 91%-107%. The RSD was 15% for Fe remained sample. This method for determination of trace gallium meets the demands of both produce and research work for super-alloys.