A three-way array model for resolving multicomponent fluorescent mixtures

Fluorescence lifetime provides a third independent dimension of information for the resolution of total luminescence spectra of multicomponent mixtures. The incorporation of this parameter into the Excitation-Emission Matrix (EEM) by the phase-modulation technique results in a three-dimensional Excitation-Emission-Frequency Array (EEFA). Multicomponent analysis based on the three-dimensional EEFA brings a qualitative change for the resolved spectra, i.e., individual spectra can be uniquely resolved, which is impossible with any two-dimensional analysis. In this paper, we present a method for analyzing the EEFA. We show mathematically that with the three-dimensional analysis of the EEFA individual spectra and lifetimes can be obtained. Our algorithm is developed in mathematical detail and demonstrated by its application to a two-component mixture.