Canadian Journal of Chemistry · 1985 · 28 citations · 1 references
Natural SciencesBiophysicsChemistryAnalytical ChemistryPhysical ChemistrySpectroscopyFluorescence SpectroscopyOptical SpectroscopyPhotochemistryPhotophysics Of Fluorescent ProbesCharge EquilibriaChromophore PhotophysicsDissociation EquilibriaFluorophore PhotophysicsPhotophysical MechanismsPorphyrin ComplexesProtonation Effects
The absorbance and fluorescence spectra of Hematoporphyrin IX, Photofrin, and Photofrin II are measured as a function of pH, concentration, and temperature, in order to isolate the ionic equilibria from the monomer/dimer/aggregate equilibria. Based on photometric and volumetric titrations, the distribution diagram for four ionic species is presented, with pK a , values of 2.7, 5.2, and 9.1. Protonation sites for these pK a 's are assigned.
1