氢化物发生-原子荧光光谱法同时测定镍基高温合金中铋和碲

采用盐酸、硝酸混合酸溶解样品,在盐酸介质中加热预还原,以柠檬酸和氟化铵作干扰抑制剂,盐酸(1+9)为载流,控制硼氢化钾的质量浓度为20 g/L,建立了氢化物发生-原子荧光光谱法同时测定高温镍基合金中痕量铋和碲的方法。实验表明:铋和碲的质量浓度均在2～10 μg/L以内与相应的荧光强度呈线性关系,方法的检出限分别为0.000 3 μg/L和0.002 μg/L。干扰试验表明:铋、碲在10 μg/L以内对彼此无干扰;加入5.0 mL 400 g/L柠檬酸溶液、5.0 mL 200 g/L氟化铵溶液可消除钴、铌、钼、铜对铋、碲测定的干扰;基体镍和主量元素铬、铁对铋、碲测定的干扰可通过基体匹配法消除。采用方法对高温镍基合金标准样品进行测定,测定值与认定值相符,结果的相对标准偏差(RSD,n=6)均不大于5％。

Simultaneous determination of bismuth and tellurium in nickel-base superalloy by hydride generation-atomic fluorescence spectrometry

The sample was dissolved with mixed acid of hydrochloric acid and nitric acid. After heating for pre-reduction in hydrochloric acid medium and controlling the mass concentration of potassium borohydride as 20 g/L, the content of bismuth and tellurium in nickel-based superalloy was simultaneously determined by hydride generation atomic fluorescence spectrometry with citric acid and ammonium fluoride as interference inhibitor and hydrochloric acid (1+9) as flow carrier. The results indicated that the fluorescence intensity of both bismuth and tellurium showed good linearity with their mass concentration in range of 2-10 μg/L. The detection limit of method for bismuth and tellurium was 0.000 3 μg/L and 0.002 μg/L, respectively. The interference test showed that bismuth and tellurium had no mutual interference when the mass concentration was less than 10 μg/L. The interference of cobalt, niobium, molybdenum and copper with bismuth and tellurium could be eliminated by adding 5.0 mL of 400 g/L citric acid solution and 5.0 mL of 200 g/L ammonium fluoride solution. The interference of matrix nickel and major components (chromium and iron) could be eliminated by matrix matching method. The proposed method was applied to the determination of nickel-based superalloy certified reference materials. The results were consistent with the certified values. The relative standard deviations (RSD, n=6) were not more than 5%.