Abstract: Recent methodological development in three-way array analysis allows unique resolution of multicomponent linear mixtures in the absence of noise. When noise is present, an iterative linearization procedure based on a least squares formulation was proposed by Appellof and Davidson, but it requires good initial guesses which may be difficult to find in practical situations. In the paper, we describe an alternative procedure based on eigenanalysis, and we discuss the relationship between the two procedures. Even though the alternative procedure does not aim to minimize the squared residuals, it is, however, non-iterative and may be used to find initial values for the least squares procedure. An example using phase-resolved fluorescence spectroscopy data seems to indicate that only minor improvement may be expected from using the least squares procedure, and, for practical purposes, the estimates from the eigenanalysis procedure may be close enough to dispense with the least squares procedure.
Key words and phrases: Nonlinear least squares, eigenanalysis, resolution of trilinear mixtures, phase-resolved, fluorescence spectrometry, alternating least squares.