Handling of first-order Rayleigh scatter in PARAFAC modelling of fluorescence excitation–emission data

The use of fluorescence spectroscopy has increased in use in recent years, mainly due to high sensitivity towards organic compounds typically present in, e.g., food products and due to the instrumental development. The extension from measuring single emission or excitation spectra to so-called emission–excitation matrices (EEM) has proven useful, increasing the selectivity between the components in the sample. However, EEMs can be rather complex and the analysis can become complicated due to interferences, scatter, overlapping signals, etc. This paper gives a comparison of several methods to handle the first-order Rayleigh scatter when PARAFAC modeling is used to decompose the three-way fluorescence data. Furthermore, the paper provides suggestion for how to handle scatter in the modeling phase.