氢化物发生-原子荧光光谱法测定银精矿中锑

为保障供需双方交易的顺利进行,需要检测银精矿中锑的含量。采用硝酸-氯酸钾-氢氟酸-硫酸溶解样品,以硫脲-抗坏血酸为预还原剂,10g/L硼氢化钾溶液为还原剂,10%(体积分数)盐酸为测定介质,实现了氢化物发生-原子荧光光谱法(HG-AFS)对银精矿中锑的测定。详细讨论了溶样方法、样品中共存元素对测定的干扰及消除方法。结果表明,采用10mL硝酸-0.5g氯酸钾-5mL氢氟酸-5mL硫酸(1+1)可将0.2g样品溶解完全;除砷外,样品中其他共存元素对锑测定的干扰可忽略;砷对锑会产生正向干扰,通过降低硼氢化钾溶液的质量浓度为10g/L可消除样品中砷对测定的干扰。在选定的实验条件下,锑质量浓度在5.00~100.0μg/L范围内与其对应的荧光强度呈线性关系,线性相关系数为0.9995,方法检出限为6×10^-2 μg/L。按照实验方法对锑质量分数为 0.01%~0.50%的银精矿样品中锑含量进行测定,结果与电感耦合等离子体原子发射光谱法(ICP-AES)相吻合,相对标准偏差(RSD,n=11)为1.0%~2.3%,按照实验方法对两个银精矿样品进行加标回收试验,加标回收率为95%~105%。

Determination of antimony in silver concentrate by hydride generation atomic fluorescence spectrometry

The content of antimony in silver concentrate should be detected to ensure the smooth transaction between the supplier and demander. The sample was dissolved with nitric acid-potassium chlorate-hydrofluoric acid-sulfuric acid system. The thiourea-ascorbic acid was used as the pre-reducing reagent and 10g/L potassium borohydride solution was used as the reducing reagent. A determination of antimony in silver concentrate by hydride generation atomic fluorescence spectrometry (HG-AFS) was realized in the medium of 10% (volume fraction) hydrochloric acid. The methods of sample dissolution as well as the interference and elimination of coexisting elements in samples were discussed in detail. The results showed that 0.2g of sample could be completely dissolved with 10.0mL of nitric acid, 0.50g of potassium chlorate, 5.0mL of hydrofluoric acid and 5.0mL of sulfuric acid (1+1). Except for arsenic, the interference of other coexisting elements with the determination of antimony could be ignored. Arsenic had positive interference with the determination of antimony, which could be eliminated by reducing the mass concentration of potassium borohydride solution to 10g/L. Under the selected experimental conditions, the mass concentration of antimony in the range of 5.00-100.0μg/L showed a linear relationship with its corresponding fluorescence intensity. The linear correlation coefficient was 0.9995. The detection limit of the method was 6×10^-2 μg/L. The content of antimony in silver concentrate samples with the mass fraction of antimony from 0.01% to 0.50% was determined according to the experimental method. The found results were consistent with those obtained by inductively coupled plasma emission spectrometry (ICP-AES), and the relative standard deviations (RSDs, n=11) were between 1.0% and 2.3%. The recovery tests of two silver concentrate samples were conducted according to the experimental method. The spiked recoveries were between 95% and 105%