火焰原子吸收光谱法测定地质样品中的砷

Determination of Arsenic in Geological Samples by Flame Atomic Absorption Spectrometry(FAAS)

微量砷的测定方法主要是原子荧光光谱法；含砷量较高的样品测定，一般采用容量法和分光光度法，但这两种方法相对来说流程长，过程繁琐。实验对样品中中等含量砷的测定进行了研究，样品经酸溶后，在硝酸（1％）介质中，用火焰原子吸收光谱法在波长193．7nm处测其吸光度，结果表明吸光度与其质量浓度在0~100μg／mL呈线性关系。方法的测定相对标准偏差（RSD）为0．8％，检出限为10．5μg／g，实验操作简便，适合样品中较高含量砷的分析测定。

Usually, trace amounts of arsenic are determined by atomic fluorescence spectrometry,whereas high concentrations of arsenicare commonly determined by volumetry or spectrophotometry. However, the above mentioned methods have some disadvantages, such as time-consuming and complicated operation procedure. In this work, a method for the determination of high contents of arsenic in geological samples by FAAS was developed. The samples were digested by concentrated nitric acid, and then in 1 ~ nitric acid medium, the contents of As were determined by FAAS at the wavelength of 193.7 nm. The results showed that the absorbance of arsenic has a linear relationship with its mass concentration in the range of 0--100 μg/mL. The relative standard deviation （RSD） was 0.8% and the detection limit was 10.5 μg/g. The proposed method is simple, and it can meet the requirements for analyzing high content As.