Laboratoire PROTEE

PROcessus de Transferts et d’Echanges dans l’Environnement

Analyse numérique des spectres de fluorescence 3D issus de mélanges non linéaires

Fluorescent mixtures are characterized by their Fluorescent Excitation Emission Matrix (FEEM). It is usualyy useful to recover the individual spectra and relative concentrations of the components in a single (or a set of) mixture(s)from their FEEM. In the first part of this thesis, we describe the phenomena of fluorescence and experimental device leading to fluorescence measurement. Several algotihms based on multilinear analysis compete to perform the perform the FEEM decomposition. The second part, is a large round up of these methods. We specially focus on the PARAFAC algorithm. Then we recall the limitation of the trilinear PARAFAC model in the description of highly concentrated mixtures. This limitation is caused by non linear screen effects due to the experimental device. We redremontrate and validate a physical model of these distortions. However, the main contribution of this thesis is the description of a new method of screen effect correction which do not need absorbance measurement. This correction can be used as a pretreatment of the PARAFAC processing. Our method is validate on three sets of severely distorted FEEM. We also discuss of two other original approaches that are not experimentally validated yet. Finally, we proposed two environmental applications of theses methods for dissolved organic matter tracing.