石墨炉原子吸收光谱法对锆及其合金中痕量镉、钼的测定

Determination of Trace Cadmium and Molybdenum in Zirconium and Its Alloys Using Graphite Furnace Atomic Absorption Spectrometry

研究了锆及其合金中痕量镉、钼的测定方法。对石墨炉原子吸收光谱法的仪器工作条件和盐酸、硝酸、氟硼酸、硫酸、混酸体系、氨水等对测定的影响,以及基体锆和共存元素对测定的干扰进行了试验,结果表明,盐酸是测定镉的主要影响因素,酸度应低,以5%为宜;氟硼酸是钼测定的主要影响因素,用量宜少;氨水浓度在1%～20%之间不影响钼的测定;基体锆对钼的测定有严重抑制作用,共存元素对测定无影响。以盐酸加氟硼酸,滴加硝酸溶解试样,定容后可直接进行镉的测定。采用氨水沉淀分离主体锆,于过滤后于滤液中可进行钼的测定。该方法适用于锆及其合金中0.1μg/g以上镉,20μg/g以上钼的测定,且快速、简便。

A rapid and simple method is developed for the determination of trace Cadmium and Molybdenum in Zirconium and its alloys using Graphite Furnac Atomic Absorption Spectrometry(GFAAS). Instrumental operating conditions and the effects of the mediums including HCl, HNO_3, H_2SO_4, HBF_4, NH_3·H_2O and the mixture of HCl-HBF_4-HNO_3, as well as zirconium matrix and coexisted elements (Fe, Cr, Ni, Sn)on the determination are tested. The results show that the main factors are HCl (to Cd) and HBF_4(to Mo). Ammonia (1%～20%) has no effect on the determination of Molybdenum, and Zirconium Matrix interferes strongly with the Mo determination, Other elements, such as Fe, Ni, Cr, Sn have no effect on it. A sample is dissolved in a mixture of HCl-HBF_4-HNO_3.Cadmium can be directly determinated by GFAAS. Molybdenum is determinated after removal of zirconium by precipitation with ammonia. The detection limits are 0.1 μg/g and 20 μg /g for Cd and Mo, respectively.