Evolving window orthogonal projections method for two-way data resolution

An evolving window orthogonal projections (EWOP) method is proposed as a new method to resolve two-way bilinear multi-component data into spectra and chromatograms of the pure constituents. The EWOP method has three main distinctive steps: (i) the zero-concentration graph (ZCG) is employed to identify the zero-concentration region directly and accurately; (ii) the so-called residue vector, which is obtained by local orthogonal projection, is used to quantify the relative concentration of a component, avoiding the effect of collinearity significantly; (iii) the component stripping can be done directly to resolve other components. The results of the simulated and real analytical system showed that the EWOP method performs well even in situations when the spectra of chemical compounds are very similar. The proposed method is also helpful for the automatic resolution of the two-way data.