NONLINEAR LEAST-SQUARES FITTING OF MULTIVARIATE ABSORPTION DATA

The Introduction of fast scanning and diode-array spectrophotometers facilitates the acquisition of large series of absorption spectra as a function of reaction time (kinetics), elution time (chromatography), or added reagent (equilibrium investigations). It Is Important to develop appropriate programs that are able to handle the wealth of data and to extract all Information. In this contribution a new application of factor analysis in a nonlinear least-squares fitting algorithm is presented. By prior factor analysis of the raw multichannel data, essential savings In memory allocation and computing time are achieved. Separation of the linear and the nonlinear parameters is accomplished and, specifically, the computation of the Jacobian is dramatically enhanced by specifically exploiting the orthonormality of the eigenvectors. The performance of the new algorithm Is compared with established programs for examples of complex equilibrium studies. © 1990, American Chemical Society. All rights reserved.