White light excitation fluorescence (WLEF) Part I. Exploring the use in analytical fluorimetry

Abstract

The hitherto unexplored scope of white light excitation fluorescence (WLEF) in analytical fluorimetry has been examined. In WLEF, the entire UV-Visible spectrum is used as the excitation source instead of selecting a particular wavelength/band pass excitation (BPE) source as is commonly done in conventional fluorescence spectroscopic methods. It is found that WLEF gives good spectral integrity, analytical sensitivity, intensity enhancement in the analysis of transparent fluorescence solutions and in the highly scattering medium with the use of difference spectrum. WLEF is shown to be a two-dimensional representation of the three-dimensional excitation–emission–matrix fluorescence (EEMF) spectrum. One of the major advantages of WLEF is that there is no need to know the excitation wavelength of an analyte, and the technique is cost saving as there is no need for band pass/cut off filters and/or a monochromator.