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三氧化钨中痕量镍的测定,推荐的方法为丁二肟萃取分离—极谱法,此法需接触剧毒物汞,且分析手续繁杂冗长。故进一步寻找选择性好、且灵敏度高的快速、简便的分析方法有一定的实际意义。 应用混合型配位络合物萃取—分光光度法测定镍已有报导,但所用显色剂均属酸性染料类。用试镉灵(Cadion)—邻菲啰啉(Phen)选择性萃取测定镍,国内未见报导。本文报告在0.2～1.5M NaOH介质中,Ni(Ⅱ)与Cadion和Phen形成红色三元络合物,并能被氯仿定量萃取。此络合物最大吸收波长位于502nm处,摩尔吸光系数为7.24×10~4,镍量在0～3.5μg/5ml范围内符合比尔定律。该络合物至少在8小时内稳定。基体钨的干扰采用沉淀分离除去。本法用于三氧化钨中痕量镍的测定,具有快速、简便、重现性好等优点。
Tungsten trioxide in the determination of trace nickel, the recommended method for the separation and extraction of butanedioxime - Polarographic method, this method should be exposed to toxic mercury, and complicated procedures lengthy. Therefore, it is of practical significance to further search for a fast and simple analytical method with good selectivity and high sensitivity. The use of mixed coordination complex extraction - spectrophotometric determination of nickel has been reported, but the developers are acidic dyes. Nickel was determined by selective extraction with Cadion-phenanthroline (Phen). It has not been reported in China. In this paper, we reported that Ni (Ⅱ) forms a red ternary complex with Cadion and Phen in 0.2-1.5M NaOH solution and can be quantitatively extracted by chloroform. The maximum absorption wavelength of this complex is located at 502nm, the molar absorptivity is 7.24 × 10 ~ 4, and the Beer’s law is obeyed in the range of 0 ~ 3.5μg / 5ml. The complex is stable for at least 8 hours. The interference of matrix tungsten is removed by precipitation separation. This method is used for the determination of trace nickel in tungsten trioxide. It has the advantages of fastness, simplicity, good reproducibility and so on.