Window target-testing factor analysis: theory and application to the chromatographic analysis of complex mixtures with multiwavelength fluorescence detection

Window target-testing factor analysis (WTTFA) is a new data analysis method that can help confirm the presence or absence of an analyte in a severely overlapped chromatogram. It is intended to be used in chromatographic appli cations with multichannel detection and is based on principal component ana lysis. The algorithm attempts to determine if the response profile of a tar get analyte lies within the response subspace of a time window containing u nresolved chromatographic peaks. Because the window moves sequentially thro ugh the chromatogram, WTTFA allows a relative assessment of match quality. To test the new method, a procedure for simulating complex chromatograms ha s been developed. The simulated data allow the limitations of WTTFA to be t ested under different conditions of chromatographic complexity, spectral ov erlap, measurement noise, window size and other factors. As a practical dem onstration of its utility, the method is applied to the chromatographic ana lysis of polycyclic aromatic compounds in a complex petroleum distillate us ing multiwavelength fluorescence detection. WTTFA indicates the presence of l-methylpyrene in an unresolved cluster of peaks. This is confirmed throug h a combination of mass spectrometry, heart-cut chromatography and self-mod eling curve resolution. (C) 1999 Elsevier Science B.V. All rights reserved.