氢化物发生-原子荧光光谱法测定锑锭及三氧化二锑中的砷

采用硫酸溶解锑锭样品，盐酸溶解三氧化二锑样品，用氢氧化钠溶液使Sb³⁺沉淀从而使基体锑与微量砷分离，通过加入硫脲-抗坏血酸将As⁵⁺还原成As³⁺，然后在原子荧光仪上测定锑锭及三氧化二锑中的砷。对氢化物发生条件进行考察，确定还原剂硼氢化钾的浓度为25 g/L、测定介质为20 %（V/V）盐酸、硫脲-抗坏血酸溶液用量为5 mL。共存元素干扰试验表明，沉淀后溶液中残留少量锑的干扰在加入1 mL酒石酸溶液后可以完全消除，而样品中其他杂质元素在加入硫脲-抗坏血酸溶液后不干扰砷的测定。方法的检出限为0.156 ng/mL 。对锑锭及三氧化二锑样品进行分析，相对标准偏差为0.95%～1.2%，测定值与国家标准方法的测定值相一致。

Determination of arsenic in antimony ingot and antimony trioxide by hydride generation-atomic fluorescence spectrometry

The antimony slab and antimonous oxide samples were dissolved by sulfuric acid and hydrochloric acid, respectively. The Sb³⁺ in solution was precipitated with sodium hydroxide to separate trace arsenic from matrix antimony. The thiourea-ascorbic acid was added to reduce As⁵⁺ to As³⁺. Then, the arsenic in antimony slab and antimonous oxide was determined by atomic fluorescence spectrometry. The hydride generation conditions were investigated: the concentration of reducing agent potassium borohydride was 25 g/L, the determination medium was 20% (V/V) hydrochloric acid, and the dosage of thiourea - ascorbic acid solution was 5 mL. The interference test of coexisting elements showed that, the interference of residual antimony in solution after precipitation could be fully eliminated by adding 1 mL of tartaric acid solution. Other impurity elements in sample did not interfere with the determination of arsenic after adding thiourea-ascorbic acid solution. The detection limit of method was 0.156 ng/mL. The antimony slab and antimonous oxide samples were analyzed by the proposed method, and the relative standard deviation (RSD) was 0.95%-1.2%. The determination results were consistent with those obtained by national standard methods.