流动注射多元校正-络合滴定法同时测定混合金属离子

SIMULTANEOUS DETERMINATION OF MIXED METAL IONS BY POTENTIOMETRIC COMPLEXOMETRIC TITRATION COUPLED WITH MULTIVARIATE CALIBRATION USING FLOW INJECTION TECHNIQUE

将流动注射应用于电位络合滴定分析法，建立了一种可同时测定混合金属离子的电位滴定方法。在该方法中，用EDTA与氟化钠的混合溶液作为滴定剂，在流通池中同时插入汞膜电极和氟离子指示电极，在滴定过程中的任一滴定点，流出液的汞电位和反应物的混合比例可由两个电极的电位测定值同时获得，从而可应用多元校正法由相应的滴定曲线求得混合金属离子中每一种组分的含量。应用该方法对混合样品中的Cu^2＋、Ph^2＋、Zn^2＋进行了同时测定，测定结果的相对标准偏差均在0．14％～0．48％（n=5）之间，回收率均在97．3％～103．9％之间。

A new potentiometric titration method coupled with multivariate calibration using flow injection technique for the simultaneous determination of mixed metal ions was developed. The titrant was a mixture of EDTA and sodium fluoride, both mercury film electrode and fluorinion selective electrode were inserted in the flow cell. In a process of titration, both the potentiometric of mer- cury ion and the volume ratio of both flowed reactants at each titration point could be obtained simultaneously from the two electrodes, then the concentration of each component in the mixture could be obtained from the titration curves by multivariate calibration method. The method was applied to the simultaneous determination of copper ion, lead ion and zinc ion in mixture samples with the relative standard deviation of 0.14% -0.48% （n = 5） and the recovery of 97.3% - 103.9%.