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应用偶氮氯膦Ⅰ作为微量镁的显色剂,已有报道,但对含大量Cu,Ni,Co,Sn,Zn等复杂合金均需分离除去干扰元素,因而费时。本文根据文献试验了直接吸光光度法测定的条件,应用亚硫酸钠,硫脲掩蔽大量铜和银,三乙醇胺掩蔽铁、铝、钛等元素,EGTA—Pb掩蔽钙、锰,乙二胺掩蔽大量镍和一定量的钴,还能抑制锌的干扰,从而提高了选择性,特别是对镍、钴、锡、锌等元素允许存在量大大提高,成功地应用于部份有色金属材料中微量镁的测定。本方法再现性好,允许较大量的干扰离子存在,测定下限可达0.005%。但因加入乙二胺的影响,摩尔吸光系数有所降低(ε_(576)=1.45×10~4)。
The application of chlorophosphonazo I as chromogenic agent for trace magnesium has been reported. However, it is time-consuming to separate and remove the interfering elements from the complex alloys containing a large amount of Cu, Ni, Co, Sn and Zn. In this paper, the direct spectrophotometric determination of the conditions according to the literature, the application of sodium sulfite, thiourea masking large amounts of copper and silver, triethanolamine masking iron, aluminum, titanium and other elements, EGTA-Pb masking calcium, manganese, ethylenediamine masked a large number of nickel and A certain amount of cobalt, but also inhibit the interference of zinc, thereby increasing the selectivity, especially for nickel, cobalt, tin, zinc and other elements allow the existence of significantly increased, successfully applied to the determination of trace amounts of magnesium in non-ferrous metals . The reproducibility of this method, allowing a larger amount of interfering ions exist, the determination of up to 0.005%. However, the molar absorptivity decreased with the addition of ethylenediamine (ε_ (576) = 1.45 × 10 ~ 4).