协同系数补偿的动力学方法用于钼和钨同时测定的研究

Simultaneous Determination of Molybdenum and Tungsten with a Kinetic Method Compensated by Synergistic Catalytic Coefficient

以Ｉ３－淀粉配合物为指示剂，用停流ＦＩＡ光度法研究了钼（ＶＩ）和钨（ＶＩ）对Ｈ２Ｏ２－Ｉ氧化还原反应体系的协同催化效应，并定义了协同催化系数Ｄ以表示这种协同作用的大小。将此系数引入到停流ＦＩＡ－动力学体系多组份同时测定的方法中，可有效地补偿吸光度对加和性的偏离，并可降低检出限。用本法测定钼（Ⅵ）和钨（Ⅵ）的线性范围分别为０～１．１μｇ·ｍｌ－１和０～２．０μｇ·ｍｌ－１，而未补偿时则分别为０～０．６μｇ·ｍｌ－１和０～０．８μｇ·ｍｌ－１。测定了钢样及模拟样品中的用和钨含量，结果满意。钼、钨的回收率分别为９７．３％～１０２．８％，９６．５％～１０２．１％，相对标准偏差ＲＳＤ分别为２．１％～２．９％，２．３％～３．４％。

The synergistic catalytic effect of molybdenum(Ⅵ)and tungsten(Ⅵ)on the hydrogen peroxide-iodide kinetic reaction systems has been studied by using I3-starch complex as indicator with stopped flow-FIA technique.The degree of synergistic effect was expressed by the proposed concept of synergistic catalytic coefficient D. The deviations from additivity of absorbance beyond given concentration ranges could be compensated by introducing the synergistic coefficient into the sim ul-taneous determination of a multiple mixture with the stopped flow -FIA method. The linear concentration ranges could be enlarged by compensating, which are 0 ～1.1μg/ ml for Mo(Ⅵ) and 0 ～2. 0 μg / ml for W(Ⅵ),respectively;while those are 0～0.6μg/ ml for Mo(Ⅵ ) and 0-0.8μg/ ml for W(Ⅵ),respectively,without being compensated, and the sensitivities also have been improved.Molybdenum and tungsten content in steel and simulated samples were determined, the recoveries and the relative standard deviations (RSD ) were 97.3%～102.8% and 2.1% ～2.9%for molybdenum, 96.5% ～102.1% and 2.3% ～3.4% for tungsten,respectively.