Time-Resolved Fluorescence Studies of Hematoporphyrin in Different Solvent Systems

Abstract

Time-resolved fluorescence studies of hematoporphyrin in aqueous solution and in different organic solvents are presented. The| observation of two exponential components in the fluorescence decay in aqueous solution reveals the presence of a monomeric and aggregated (probably dimeric) form of the molecule, as confirmed by absorption and fluorescence measurements. The slow component (~ 15 ns in aqueous solution) and the fast one (~ 3.8 ns in aqueous solution) are attributed to monomers and dimers, respectively. Higher aggregated species of hematoporphyrin are also present, which are essentially devoid of fluorescence properties.