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经常会对金属精炼和生产者提出一些新的、更苛刻的要求以获得更纯的材料。这些要求最终将会归总到仪器生产厂家,厂家的技术人员就需要开发新的分析方法以改进对各种各样金属中存在的不希望有杂质的检测能力。直至最近,使用传统的直流电弧或火花激发光源的直读多色仪一直都以可接受的检出限提供着快速而可靠的分析结果。但是,灵敏度的改善则只有通过改变仪器方法(例如ICP-AES和石墨炉AAS)才可能实现。这样做,需要兼顾样品制备时间和分析所需样品量这两个方面。当前,新的对痕量杂质的分析需求已要求我们把每种早先分析方法的速度和简易性与一些新方法的灵敏度结合起来。在作者的早先论文中曾叙述过利用背景区域作为内标可大大改善分析几种铝合金时磷的检出限。用分析线对背景之比值代替经典的铝内标线的方法可以有很好的精密度准确地测定低至3ppm水平的磷。同一技术已被用于分析电解精制而得的铜,测定其中的Se和Te,精密度和灵敏度也同样得到了很大的改善。以前,Se和Te只能可靠地测至1—3ppm水平,而现在,已可测定0.1ppmTe和0.3ppm Se。在测定镁合金痕量Fe和Ni的分析中也已观测到了类似的改进。
Often, new and tougher requirements for metal refining and producers are put forward to obtain more pure materials. These requirements will eventually be back to the instrument manufacturer, and the manufacturer’s technicians will need to develop new analytical methods to improve the detection of unwanted impurities in a wide variety of metals. Until recently, direct reading polychromators using conventional DC arc or spark excitation sources have provided fast and reliable analysis with acceptable limits of detection. However, the improvement in sensitivity is only possible by changing instrumental methods such as ICP-AES and graphite furnace AAS. Doing so requires taking into account both sample preparation time and the amount of sample required for the analysis. At present, new analytical needs for trace impurities have required us to combine the speed and simplicity of each of the previous analytical methods with the sensitivity of some of the new methods. In the author’s previous paper, it was described that the use of the background area as an internal standard greatly improves the detection limit of phosphorus when analyzing several aluminum alloys. The method of substituting the ratio of the analytical line to the background instead of the classic aluminum internal standard line allows for the accurate determination of phosphorus as low as 3 ppm. The same technique has been used for the analysis of electrolytic refined copper, the determination of which Se and Te, precision and sensitivity have also been greatly improved. Se and Te have previously only reliably measured levels of 1-3 ppm, and now 0.1 ppm Te and 0.3 ppm Se have been measured. A similar improvement has also been observed in the determination of trace amounts of Fe and Ni in magnesium alloys.