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本文探究了一种仅以铅空心阴极灯作为光源,用火焰原子吸收光谱法(FAAS)同时测定铜合金中的铅和锌的方法。以硝酸消解样品,加入过量的碘化钾使铜离子生成碘化亚铜沉淀,过滤分离。向分离出来的滤液中加入过量的二乙基二硫代氨基甲酸钠(DDTC-Na),使其中的铅和锌形成不溶性的Pb(DDTC)2和Zn(DDTC)2,用三氯甲烷萃取后首先在283.2nm波长下进行FAAS(锌在此波长无吸收)测定得铅的含量,再加入过量的Pb(Ⅱ)将Zn(Ⅱ)从Zn(DDTC)2中置换出来,此时再在相同波长下测定有机相中铅的吸光度,增加的吸光度的值即为锌的含量。本法简单快速,一次处理样品且不需要更换空心阴极灯即可同时测定两种元素。本方法铅和锌的线性范围皆为0.2-14ug/ml,回收率分别为99.33-102.03%和98.97-102.34%,测定下限可分别达到3.5×10-5和4.9×10-5,准确度和精密度完全能满足工业分析要求。
This paper explores a method for the simultaneous determination of lead and zinc in copper alloys by flame atomic absorption spectrometry (FAAS) using only lead-acid hollow cathode lamps as light sources. To nitric acid digestion samples, adding excessive potassium iodide so that copper ions generated precipitation of copper iodide, filtered and separated. An excess of sodium diethyldithiocarbamate (DDTC-Na) is added to the separated filtrate to make lead and zinc insoluble Pb (DDTC) 2 and Zn (DDTC) 2, which is extracted with chloroform First, the Pb content of FAAS (zinc is not absorbed at this wavelength) is measured at 283.2 nm, and then Zn (II) is replaced from Zn (DDTC) 2 by excess Pb (II) Determination of the absorbance of lead in the organic phase at the wavelength, the value of the increased absorbance is the zinc content. This method is simple and fast, processing samples at once and measuring both elements without the need to replace a hollow cathode lamp. The linear range of this method for lead and zinc were 0.2-14ug / ml, the recovery rates were 99.33-102.03% and 98.97-102.34% respectively, and the lower limit of determination was 3.5 × 10-5 and 4.9 × 10-5, respectively. The accuracy and Precision can fully meet the requirements of industrial analysis.