计算光谱配位滴定法同时测定钙和镁

建立了一种将光谱配位滴定分析法与化学计量学相结合同时测定混合金属离子的新方法。在这种方法中，滴定剂是由EDTA和两种指示剂组成的混合溶液。滴定过程中滴定剂的加入体积和滴定反应进程可由吸收光谱通过计算同时获得，并进一步得到滴定曲线。应用滴定曲线可建立相应的矩阵方程，从而可应用主成分回归法计算金属混合物中各组分的浓度。该方法只需要光谱信息就可得到分析结果，免去了对体积的计量，因此方法简便，准确。应用该方法以孔雀绿和Cu-PAN为指示剂对钙和镁的混合溶液进行了同时测定，结果满意。

Simultaneous Determination of Calcium and Magnesium by Calculative Spectrophotometric Complexometric Titration

A new spectrophotometric complexometric titration method coupled with chemometrics for the determination of mixtures of metal ions has been developed. In the method described here, the titrant is a mixture of EDTA and two indicators. In the process of titration, both the volumetric addition of titrant and the progress of titration reaction can be characterized simultaneously by chemometric calculation with the absorption spectra, and then the titration curves can be obtained. With the titration curves, a matrix equation can be established, and thus the concentration of each component in the mixture of metal ions can be calculated with principal component regression. The method only needs the information of absorption spectra to obtain the analytical results, and is free of volumetric measurements. So the method is simple, convenient and precise, and has been applied to the simultaneous determination of mixtures of calcium and magnesium using malachite green and Cu-PAN as indicators with satisfactory results.