氢化物发生-原子荧光光谱法测定精碲中微量砷

提出了一种氢化物发生-原子荧光光谱法测定精碲中微量砷的方法。用硝酸溶解样品,氢氧化钾和盐酸调节溶液酸度至pH 5.5~6.5,碲水解沉淀析出。除去了大量基体后,溶液中碲量少于50μg/mL。在盐酸介质中用硫脲-抗坏血酸将砷(预还原为砷(Ⅲ),以标准加入法绘制校准曲线,氢化物发生-原子荧光光谱法测定砷量。方法的检出限为0.02μg/L,砷量在0.02~40μg/L范围内有良好的线性关系。方法操作简便、快速,应用于精碲中痕量砷的测定,测定结果与正戊醇萃取砷钼蓝分光光度法的结果相符,相对标准偏差为4.2%~8.5%,样品的加标回收率在93%~104%之间。

Hydride generation-atomic fluorescence spectrometry for the determination of micro arsenic in refined tellurium

A hydride generation-atomic fluorescence spectrometric method was proposed for the determination of trace arsenic in refined tellurium. After the samples were dissolved in HNO_3, the solution was adjusted to pH 5.5-6.5 with KOH and HCl to get tellurium precipitated through hydrolysis. After removal of a great amount of matrix, the content of tellurium in solution was below 50 μg/mL. In HCl, As(Ⅴ) was reduced to As(Ⅲ) with thiourea-ascorbie acid. The calibration curves were plotted by standard addition method, and the content of arsenic was determined by hydride generation-atomic fluorescence spectrometry. The detection limit of this method was 0.02 g/L. The linearity of calibration curve was good for arsenic in the range of 0. 02-40 g/L. Being simple and rapid, the propesed method was applied to the determination of trace arsenic in refined tellurium. The results were in good agreement with those obtained by GB method. The relative standard deviations (RSDs) were in 4.2%-8. 5 %, and the recoveries of standard addition were in the range of 93 %-104 %.