Study on the Method for the Determination of Trace Boron, Molybdenum, Silver, Tin and Lead in Geochemical Samples by Direct Current Arc Full Spectrum Direct Reading Atomic Emission Spectroscopy (DC-Arc-AES)
HAO Zhi-hong, YAO Jian-zhen, TANG Rui-ling, ZHANG Xue-mei, LI Wen-ge, ZHANG Qin*
Institute of Geophysical and Geochemical Exploration, Chinese Academy of Geological Sciences, Langfang 065000, China
Abstract：The method for the determination of trace boron, molybdenum, silver, tin and lead in geochemical samples by direct current arc full spectrum direct reading atomic emission spectroscopy (DC-Arc-AES) was established. Direct current arc full spectrum direct reading atomic emission spectrometer with a large area of solid-state detectors has functions of full spectrum direct reading and real-time background correction. The new electrodes and new buffer recipe were proposed in this paper, and have applied for national patent. Suitable analytical line pairs, back ground correcting points of elements and the internal standard method were selected, and Ge was used as internal standard. Multistage currents were selected in the research on current program, and each current set different holding time to ensure that each element has a good signal to noise ratio. Continuous rising current mode selected can effectively eliminate the splash of the sample. Argon as shielding gas can eliminate CN band generating and reduce spectral background, also plays a role in stabilizing the arc, and argon flow 3.5 L·min-1 was selected. Evaporation curve of each element was made, and it was concluded that the evaporation behavior of each element is consistent, and combined with the effects of different spectrographic times on the intensity and background, the spectrographic time of 35s was selected. In this paper, national standards substances were selected as a standard series, and the standard series includes different nature and different content of standard substances which meet the determination of trace boron, molybdenum, silver, tin and lead in geochemical samples. In the optimum experimental conditions, the detection limits for B, Mo, Ag, Sn and Pb are 1.1, 0.09, 0.01, 0.41, and 0.56 μg·g-1 respectively, and the precisions (RSD, n=12) for B, Mo, Ag, Sn and Pb are 4.57%～7.63%, 5.14%～7.75%, 5.48%～12.30%, 3.97%～10.46%, and 4.26%～9.21% respectively. The analytical accuracy was validated by national standards and the results are in agreement with certified values. The method is simple, rapid, is an advanced analytical method for the determination of trace amounts of geochemical samples’ boron, molybdenum, silver, tin and lead, and has a certain practicality.
Key words：Direct current arc of full spectrum direct reading atomic emission spectroscopy;Geochemical samples;Boron;Molybdenum;Silver;Tin;Lead
郝志红，姚建贞，唐瑞玲，张雪梅，李文阁，张 勤* . 直流电弧全谱直读原子发射光谱法(DC-Arc-AES)测定地球化学样品中痕量硼、钼、银、锡、铅的方法研究 [J]. 光谱学与光谱分析, 2015, 35(02): 527-533.
HAO Zhi-hong, YAO Jian-zhen, TANG Rui-ling, ZHANG Xue-mei, LI Wen-ge, ZHANG Qin* . Study on the Method for the Determination of Trace Boron, Molybdenum, Silver, Tin and Lead in Geochemical Samples by Direct Current Arc Full Spectrum Direct Reading Atomic Emission Spectroscopy (DC-Arc-AES). SPECTROSCOPY AND SPECTRAL ANALYSIS, 2015, 35(02): 527-533.
