Chemical rank estimation by multiresolution analysis for two-way data in the presence of background

Resolution methods based on factor analysis are powerful approaches for qualitative and quantitative analysis of unknown multicomponent systems. A reliable assessment of the number of chemical species in the investigated system is of prime importance for a successful resolution. Unfortunately, this is confused very much in practice by instrumental and experimental difficulties. Spectral background and chromatographic drift are two of the most serious problems, which hamper not only the determination of the number of components in the analytical system, but also the final resolution of the mixture. In this paper, multiresolution analysis (MA) based on orthogonal wavelet bases is introduced to remove the influence of complex backgrounds and furthermore to correctly determine the number of components in a system. Making use of properties of backgrounds in two-way chromatographic data, the method needs no special assumption imposed upon the profiles of the baseline and the background spectra. Thus, most kinds of background can be eliminated regardless of their behaviors. Satisfactory results from computer simulation and real analytical systems illustrate the feasibility of the proposed procedure.