Role of non-fluorescent chromophores in inner filter effect correction and PARAFAC decomposition

Elfrida M Carstea; Stéphane Mounier; Roland Redon; Cristina L Popa

doi:10.1016/j.saa.2019.117878

Role of non-fluorescent chromophores in inner filter effect correction and PARAFAC decomposition

Spectrochim Acta A Mol Biomol Spectrosc. 2020 Mar 15:229:117878. doi: 10.1016/j.saa.2019.117878. Epub 2019 Dec 2.

Authors

Elfrida M Carstea¹, Stéphane Mounier², Roland Redon², Cristina L Popa³

Affiliations

¹ National Institute of R&D for Optoelectronics, Atomistilor 409, 077125 Magurele, Romania. Electronic address: elfrida.carstea@inoe.ro.
² Univ Toulon, Aix Marseille Univ., CNRS/INSU, IRD, MIO UM 110, Mediterranean Institute of Oceanography, La Garde, France.
³ National Institute of R&D for Optoelectronics, Atomistilor 409, 077125 Magurele, Romania. Electronic address: cristina.popa@inoe.ro.

PMID: 31813717
DOI: 10.1016/j.saa.2019.117878

Abstract

Numerous studies have shown the impact of inner filter effect (IFE) on the fluorescence signal. IFE reduces the fluorescence intensity and distorts the fluorescence peak shape and position, through the absorption of the emitted radiation by the sample components. In this study, we aimed to understand the role of a non-fluorescing chromophore in IFE correction and PARAFAC decomposition. Solutions of three fluorophores, tryptophan, fluorescein and quinine sulfate, and an absorbing compound, green ink, have been prepared using the controlled dilution approach (CDA). PARAFAC identified three components associated with quinine sulfate, fluorescein and an IFE artifact, which was caused by a shift in peak position. Results showed that the absorption of the chromophore played an important role in component determination. We observed that CDA-PARAFAC was able to correct the quinine sulfate and fluorescein signals, and to suppress the IFE artifact component. However, the method was not effective in removing the IFE impact at high concentrations. The results have significant implications on the analysis of samples that contain complex mixtures of fluorophores and chromophores, such as colored natural organic matter or nutrients, like NO₃^2-.

Keywords: Controlled dilution approach; Fluorescence spectroscopy; Inner filter effect; PARAFAC.