Spectrophotometric Analysis of a Two-Component System with Overlapping Spectra by Walter Rohr

A number of methods have been developed to determine the composition of a binary
mixture spectrophotometrically. Most of these are directed at mixtures where one
component can be isolated from the other or they require a Beer’s law experiment to
measure the molar absorptivity of each of the substances in the mixture. However,
Blanco 1, et. al. described a method of resolving mixtures with overlapping spectra, called
Multi-Wavelength Linear Regression Analysis or MLRA, without determining molar
absorptivities or complicated mathematics. Using Blanco’s method, the composition of a
binary mixture with overlapping spectra can be resolved with only three measurements,
the absorbance of a standard solution for each component, and the unknown mixture
itself. Vernier’s Logger Pro software is ideally suited for this experiment with the ease at
which one can manipulate data and its ability to prepare a graph even when the data are
out of order


http://www.vernier.com/files/innovate/spectralanalysis3.pdf