The method of subwindow factor analysis (SFA) is introduced as a solution to the problem of directly extracting component spectra from overlapping structures obtained from hyphenated chromatography without first resolving concentration profiles. This is of advantage when a complete resolution cannot be obtained or is of less interest in the analytical situation. The method is based upon comparisons of chromatographic regions (subwindows) which have only one eluting component in common. The paper presents the theory and an application to a structure with 4 overlapping components from a data set from a mixture of polyaromatic hydrocarbons recorded by high-performance liquid chromatography diode array detection (HPLC-DAD). (C) 1999 Elsevier Science B.V. All rights reserved.