A METHOD FOR THE DETERMINATION OF REACTION-MECHANISMS AND RATE CONSTANTS FROM 2-WAY SPECTROSCOPIC DATA

We propose a method for resolving spectroscopic reaction monitoring da ta into concentration profiles and spectra for the pure chemical compo nents. It can be used if a valid mechanistic model for the reaction ca n be postulated. In the analysis, the parameters of the model, i.e. th e rate constants, are also determined. If several mechanistic models a re possible, these can be tested and the model best describing the dat a can be selected. The method is based on refinement of concentration profiles from the mechanistic model by target testing. Subsequent rota tion of the loadings from principal component analysis (PCA) yields th e pure component spectra. The only input used is the spectroscopic dat a, the mechanistic model(s) to be tested/fitted and possibly, but not necessarily, the initial concentrations of the species participating i n the reaction. The performance of the method has been evaluated for s ynthetic and experimental data described by some common and simple rea ction models. A comparison with techniques for non-linear least square s fitting and self-modelling curve resolution is included in the text. (C) 1998 Elsevier Science B.V. All rights reserved.