Resolution of multicomponent overlapped peaks by the orthogonal projection approach, evolving factor analysis and window factor analysis

The orthogonal projection approach (OPA), a stepwise approach developed for the determination of the number of compounds present in a multicomponent system, has been extended by including a step that allows the chromatographic and spectroscopic pure compound profiles to be determined. This is done using an alternating least-squares procedure. The initial estimations are the spectra selected in the first step of OPA. The performance of the OPA algorithm is compared with that of two window-based self-modelling curve resolution approaches: evolving factor analysis (EFA) and window factor analysis (WFA).