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原子吸收法测定铅的灵敏度较低,常常应用有机试剂萃取富集,氢化物测定铅的条件非常苛刻,存在着一定的干扰。本文用氮-氢火焰考察了酒石酸-重铬酸钾-亚铁氰化钾体系中氢化法测铅的条件及共存离子的干扰,在酒石酸-重铬酸钾、硝酸-过氧化氢及硝酸-过硫酸铵三个体系中,加入亚铁氰化钾,使灵敏度提高了12倍。为克服镍、铜、铁等共存元素对测定的影响,采用硫酸锶共沉淀法进行分离,成功地测定了高温合金中的铅。方法适于镍基合金中0.0001—0.002%铅的测定,检出限为0.014微克/毫升;测定0.0005%的铅,变异系数为12.6%。一、仪器与试剂WFX-1A型原子吸收分光光度计;本所自制AHG-1型半自动氢化物装置。
Atomic absorption method for the determination of low sensitivity of lead, often using organic reagents enrichment, the determination of lead hydride conditions are very harsh, there is a certain disturbance. In this paper, the conditions of tartaric acid - potassium dichromate - potassium ferrocyanide hydrogenation method for the determination of lead and the interference of coexisting ions were investigated in the system of tartaric acid - potassium dichromate - potassium ferrocyanide. In tartaric acid - potassium dichromate, nitric acid - hydrogen peroxide and nitric acid - Ammonium persulfate three systems, adding potassium ferrocyanide, the sensitivity increased by 12 times. In order to overcome the influence of co-existing elements such as nickel, copper and iron on the determination, strontium sulfate coprecipitation method was used to separate the lead in the superalloys. The method is suitable for the determination of 0.0001-0.002% lead in nickel-based alloys with a detection limit of 0.014 μg / ml; 0.0005% lead is determined with a coefficient of variation of 12.6%. First, instruments and reagents WFX-1A atomic absorption spectrophotometer; our own AHG-1 semi-automatic hydride device.