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用分光光度法对镧系(Ⅲ)离子(Ln~(3+))—偶氮氯膦-mA(CPA-mA)—二安基比林甲烷(DAM)三元体系在水—乙醇介质中进行了研究。形成的异配三元配合物的组成为Ln~(3+):CPA-mA:DAM=1:2:1,摩尔吸光吸系数ε=9.4×10~4～1.3×10~5。用EDTA—VO_2~+系统作为掩蔽与保护剂可以消除干扰离子的影响,对低含量的稀土材料的分析有一定的实用价值。偶氮氯瞵—mA作为变色酸双偶氮显色剂问世以来,由于其灵敏度高、显色酸度高、稳定性好、操作简便等优点而引起人们的兴趣。但截至目前,对稀土元素的测定多利用其二元配合物。我们发现在PH3.0～3.6的介质中于二元配合物中加入二安替比林甲烷时,溶液的吸光值明显增大,所生成的三元配合物稳定性也高,但某些离子干扰严重。若在体系中加入一定比例的EDTA-VO_2~+时,可显著消除干扰,同时可在一定范围内掩蔽重稀土以达到定量测定轻稀土的目的。
Spectrophotometric determination of lanthanide (Ⅲ) ion (Ln ~ (3 +)) - chlorophosphonazo-mA (CPA-mA) -dianabile methane (DAM) ternary system in water- Were studied. The composition of the heterocomplex ternary complex formed is Ln ~ (3 +): CPA-mA: DAM = 1: 2: 1 and the molar absorption coefficient ε = 9.4 × 10 ~ 4 ~ 1.3 × 10 ~ 5. Using EDTA-VO_2 ~ + system as a masking and protecting agent can eliminate the influence of interfering ions, and has some practical value for the analysis of low content rare earth materials. Since azo chromogen-mA was developed as a chromotropic acid disazo chromogenic agent, it has aroused people’s interest because of its high sensitivity, high color acidity, good stability and easy operation. But so far, the determination of rare earth elements to make more use of its binary complexes. We found that when the diantipyrylmethane was added to the binary complexes in the medium of pH3.0 ~ 3.6, the absorbance of the solution increased obviously and the stability of the ternary complex formed was also high. However, some ions Serious interference. If a certain proportion of EDTA-VO_2 ~ + is added to the system, the interference can be obviously eliminated, and heavy rare earths can be masked within a certain range in order to achieve the quantitative determination of light rare earths.