Characterization of Photoproducts of m-THPP in Aqueous Solution

Authors

  • Natacha Lourette,

    1. Laboratoire de Spectrométrie de Masse et de Chimie Laser (LSMCL), Univesité Paul Verlaine-Metz, Institut de Physique et d'Electronique de Metz (IPEM), Metz, France
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  • Benoît Maunlt,

    1. Laboratoire de Spectrométrie de Masse et de Chimie Laser (LSMCL), Univesité Paul Verlaine-Metz, Institut de Physique et d'Electronique de Metz (IPEM), Metz, France
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  • Lina Bezdetnaya,

    1. Centre Alexis Vautrin, Centre de Recherche en Automatique de Nancy (CRAN) National de la Recherche Scientifique (CNRS) Unité Mixte de Recherche (UMR) 7039, Cedex, France.
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  • Henri-Pierre Lassalle,

    1. Centre Alexis Vautrin, Centre de Recherche en Automatique de Nancy (CRAN) National de la Recherche Scientifique (CNRS) Unité Mixte de Recherche (UMR) 7039, Cedex, France.
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  • Françols Guillemin,

    1. Centre Alexis Vautrin, Centre de Recherche en Automatique de Nancy (CRAN) National de la Recherche Scientifique (CNRS) Unité Mixte de Recherche (UMR) 7039, Cedex, France.
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  • Jean-François Muller

    Corresponding author
    1. Laboratoire de Spectrométrie de Masse et de Chimie Laser (LSMCL), Univesité Paul Verlaine-Metz, Institut de Physique et d'Electronique de Metz (IPEM), Metz, France
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  • Posted on the website on 2 February 2005

*To whom correspondence should be addressed: Laboratoire de Spectrométrie de Masse et de Chimie Laser (LSMCL), Université de Metz, Institut de Physique et d'Electronique de Metz (IPEM) 1 Bd Arago, Metz-Technopôle, F-57078 Cedex 03, Metz, France. Fax: 33-387-31-5851; e-mail: jfmuller@sciences.univ-metz.fr

ABSTRACT

This study examined the nature of photoproducts after pulse laser irradiation (647.5 nm) of 5,10,15,20-tetrakis(meso-hydroxyphenyl)porphyrin (m-THPP) (10 μmol/L) in ethanol-water (1/99, vol/vol) solution. Spectroscopic measurements (UV-visible absorption and fluorescence) and mass spectrometry techniques (matrix-assisted laser desorption-ionization [MALDI] coupled with time-of-flight mass spectrometer [TOF-MS] or tandem time of flight mass spectrometer [TOF/TOF-MS]) were used to follow photomodifications. Spectroscopic measurements evidenced photomodification as the main process after m-THPP irradiation. Three oxidized photoproducts at m/z 693.25, 695.24 and 713.25 were characterized by MS. After prolonged irradiation new isotopic distributions were registered at m/z 1355.41, 2031.57, 2707.80 and 3383.98 with MALDI-TOF-MS and TOF/TOF-MS. These new photoproducts were attributed to covalent oligomeric structures as dimer, trimer, tetramer and pentamer of m-THPP.

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