β修正光度法测定镉络合物特征参数

β-Correction Spectrophotometry for Determination of Cadmium Chelate’s Characteristic Parameters

利用β修正分析理论建立金属络合体系中络合物组成及其摩尔吸光系数数学方程，研究了镉（Ⅱ）－丁基罗丹明Ｂ（ＢＲｈＢ）－碘（Ⅰ－）缔合反应体系，结果表明，镉与ＢＲｈＢ组成比为１：２，缔合产物在６１０ｎｍ波长处摩尔吸光系数比其表观值高△ε６１０＝０．９１×１０４Ｌ．ｍｏｌ－１．ｃｍ－１。

With the aid of the β-correction principle, the mathematical expressions for both the complex composition-ratio and the true molar absorptivity of chelates have been derived. The color reaction between Cd(Ⅱ)and butyl Rhodamine B(BRhB)at pH 3 in the presence of potassium iodide has been studied for the determination of composition-ratio and molar absorptivity. The results shew, both the precision and sensitivity of the β-correction method are higher than those of the single wavelength method. The ratio of Cd + BRhB is 1+2, while the discrepancy between the true and the apparent molar absorptivity of Cd (BRhB)2 is 0.91×104L.mol-1.cm-1.