交流电弧发射光谱法测定地球化学样品中银锡硼

对于地球化学样品中银、锡、硼元素的检测通常采用电弧原子发射光谱法,但是,传统的分析方法需要依靠相板记录,采用计算机定量译谱,分析过程繁琐,而且分析结果受相板质量及人为因素影响较大。采用改装后具有直读功能的CCD-I型交流电弧发射光谱仪,可对地球化学样品中的痕量银、锡、硼进行快速测定,取代了传统的相板记录及洗相译谱等繁琐的操作程序,提高了测试效率。实验建立了交流电弧发射光谱法测定地球化学样品中银、锡、硼的分析方法,试验了不同缓冲剂及工作条件对银、锡、硼测定的影响。选择K_2S_2O_7、Al_2O_3、NaF、KI和碳粉的混合物为固体缓冲剂,采用内标法,以锗(Ge)作为内标元素;选择合适的分析线对,以不同的激发时间进行摄谱绘制各元素的蒸发曲线,得出最佳激发时间为30s。通过扣除分析线和内标线背景,能有效消除基体对测定结果的影响,得到了较好的分析结果,各元素校准曲线的相关系数均不小于0.999 0。在优化的实验条件下,方法检出限为:0.015μg/g(银),0.45μg/g(锡),0.90μg/g(硼)。选取7个国家一级地球化学标准物质进行精密度考察,各元素测定结果的相对标准偏差(RSD,n=12)均小于10%;采用实验方法对岩石、土壤、水系沉积物国家一级标准物质进行测定,结果与认定值相符。

Determination of sliver,tin and boron in geochemical sample by alternating current(AC) arc emission spectrometry

The elements of silver, tin and boron in geochemical sample are usually determined by arc atomic emission spectrometry. However, the conventional analysis method requires phase plate record and quantitative spectra interpretation by computer. The analytical procedures are complicated, and the results are greatly influenced by phase plate quality and human factors. The refitted direct-reading CCD-I alternating current(AC) arc emission spectrometer was used for the rapid determination of trace silver, tin and boron in geochemical sample. The time-consuming operation procedures of phase plate record and spectra interpretation in conventional method were replaced, which improved the testing efficiency. The analysis method of silver, tin and boron in geochemical sample by AC arc emission spectrometry was established. The influence of various buffer reagents and working conditions on the determination of silver, tin and boron was investigated. The mixture of K₂S₂O₇, Al₂O₃, NaF, KI and carbon powder was used as solid buffer reagent. The internal standard method was selected with Ge as internal standard element. The proper analysis line pair were used to prepare the evaporation curves of elements with different excitation time. It was found that the optimal excitation time was 30 s. The matrix effect was eliminated by background detection of analysis line and internal standard line. The analytical results were good. The correlation coefficients of calibration curves of elements were not less than 0.999 0. The detection limit under optimal experimental conditions was as follows: 0.015 μg/g for silver, 0.45 μg/g for tin and 0.90 μg/g for boron. The precision test was conducted with seven national primary geochemical certified reference materials, and the relative standard deviations (RSD, n=12) were less than 10%. The proposed method was applied to the determination of national primary certified reference materials of rock, soil and stream sediments, and the results were consistent with the certified values.